My name is Solène Rapenne. I like to learn and share my knowledge with other. With this blog I can share my experiences and issues. Some of my interests : '(BSD OpenBSD h+ Lisp Emacs cli-tool gaming internet-infrastructure Crossbow). I love % and lambda characters. OpenBSD Developer solene@.

Contact : solene on Freenode or solene+www at dataswamp dot org

This website is generated using cl-yag. A gopher version is available here

If you like what I write, you can give me a tip at donate at perso dot pw through Paypal.

# Generate qrcode using command line

Written by Solène, on 14 July 2018.
Tags: #unix

If you need to generate a QR picture using command line tool. I would recommend libqrencode.

qrencode -o file.png 'some text'


It’s also possible to display the QR code inside the terminal with the following command.

qrencode -t ANSI256 'some text'


Official qrencode website

# Tmux mastery

Written by Solène, on 05 July 2018.
Tags: #unix

Tips for using Tmux more efficiently

### Enter in copy mode

By default Tmux uses the emacs key-bindings, to make a selection you need to enter in copy-mode by pressing Ctrl+b and then [ with Ctrl+b being the tmux prefix key, if you changed it then do the replacement while reading.

### Make a selection

While in copy-mode, selects your start or ending position for your selection and then press Ctrl+Space to start the selection. Now, move your cursor to select the text and press Ctrl+w to validate.

### Paste a selection

When you want to paste your selection, press Ctrl+b ] (you should not be in copy-mode for this!).

### Make a rectangle selection

If you want to make a rectangular selection, press Ctrl+space to start and immediately, press R (capitalized R), then move your cursor and validate with Ctrl+w.

### Output the buffer to X buffer

Make a selection to put the content in tmux buffer, then type

tmux save-buffer - | xclip


You may want to look at xclip (it’s a package) man page.

### Output the buffer to a file

tmux save-buffer file


### Load a file into buffer

It’s possible to load the content of a file inside the buffer for pasting it somewhere.

tmux load-buffer file


You can also load into the buffer the output of a command, using a pipe and - as a file like in this example:

echo 'something very interesting' | tmux load-buffer -


### Display the battery percentage in the status bar

If you want to display your battery percentage and update it every 40 seconds, you can add two following lines in ~/.tmux.conf:

set status-interval 40
set -g status-right "#[fg=colour155]#(apm -l)%% | #[fg=colour45]%d %b %R"


This example works on OpenBSD using apm command. You can reuse this example to display others informations.

# Writing an article using mdoc format

Written by Solène, on 03 July 2018.
Tags: #unix

I never wrote a man page. I already had to read at the source of a man page, but I was barely understand what happened there. As I like having fun and discovering new things (people call me a Hipster since last days days ;-) ).

I modified cl-yag (the website generator used for this website) to be only produced by mdoc files. The output was not very cool as it has too many html items (classes, attributes, tags etc…). The result wasn’t that bad but it looked like concatenated man pages.

I actually enjoyed playing with mdoc format (the man page format on OpenBSD, I don’t know if it’s used somewhere else). While it’s pretty verbose, it allows to separate the formatting from the paragraphs. As I’m playing with ed editor last days, it is easier to have an article written with small pieces of lines rather than a big paragraph including the formatting.

Finally I succeded at writing a command line which produced an usable html output to use it as a converter in cl-yag. Now, I’ll be able to write my articles in the mdoc format if I want :D (which is fun). The convert command is really ugly but it actually works, as you can see if you read this.

cat data/%IN  | mandoc -T markdown | sed -e '1,2d' -e '$d' | multimarkdown -t html -o %OUT  The trick here was to use markdown as an convert format between mdoc to html. As markdown is very weak compared to html (in possibilities), it will only use simple tags for formatting the html output. The sed command is needed to delete the mandoc output with the man page title at the top, and the operating system at the bottom. By having played with this, writing a man page is less obscure to me and I have a new unusual format to use for writing my articles. Maybe unusual for this use case, but still very powerful! # Trying to move away from emacs Written by Solène, on 03 July 2018. Tags: #unix #emacs Hello Today I will write about my current process of trying to get rid of emacs. I use it extensively with org-mode for taking notes and making them into a agenda/todo-list, this helped me a lot to remember tasks to do and what people told to me. I also use it for editing of course, any kind of text or source code. This is usually the editor I use for writing the blog articles that you can read here. This one is written using ed. I also read my emails in emacs with mu4e (which last version doesn’t work anymore on powerpc due to a c++14 feature used and no compiler available on powerpc to compile it…). While I like Emacs, I never liked to use one big tool for everything. My current quest is to look for a portable and efficient way to replace differents emacs parts. I will not stop using Emacs if the replacements are not good enough to do the job. So, I identified my Emacs uses: • todo-list / agenda / taking notes • writing code (perl, C, php, Common LISP) • IRC • mails • writing texts • playing chess by mail • jabber client I will try for each topic to identify alternatives and challenge them to Emacs. ## Todo-list / Agenda / Notes taking This is the most important part of my emacs use and it is the one I would really like to get out of Emacs. What I need is: writing quickly a task, add a deadline to it, add explanations or a description to it, be able to add sub-tasks for a task and be able to display it correctly (like in order of deadline with days / hours before deadline). I am trying to convert my current todo-list to taskwarrior, the learning curve is not easy but after spending one hour playing with it while reading the man page, I have understood enough to replace org-mode with it. I do not know if it will be as good as org-mode but only time will let us know. By the way, I found vit, a ncurses front-end for taskwarrior. ## Writing code Actually Emacs is a good editor. It supports syntax coloring, can evaluates regions of code (depend of the language), the editor is nice etc… I discovered jed which is a emacs-like editor written in C+libslang, it’s stable and light while providing more features than mg editor (available in OpenBSD base installation). While I am currently playing with ed for some reasons (I will certainly write about it), I am not sure I could use it for writing a software from scratch. ## IRC There are lots of differents IRC clients around, I just need to pick up one ## Mails I really enjoy using mu4e, I can find my mails easily with it, the query system is very powerful and interesting. I don’t know what I could use to replace it. I have been using alpine some times ago, and I tried mutt before mu4e and I did not like it. I have heard about some tools to manage a maildir folder using unix commands, maybe I should try this one. I did not any searches on this topic at the moment. ## Writing text For writing plain text like my articles or for using$EDITOR for differents tasks, I think that ed will do the job perfectly :-) There is ONE feature I really like in Emacs but I think it’s really easy to recreate with a script, the function bind on M-q to wrap a text to the correct column numbers!

Update: meanwhile I wrote a little perl script using Text::Wrap module available in base Perl. It wraps to 70 columns. It could be extended to fill blanks or add a character for the first line of a paragraph.

#!/usr/bin/env perl
use strict;use warnings;
use Text::Wrap qw(wrap $columns); open IN, '<'.$ARGV[0];
$columns = 70; my @file = <IN>; print wrap("","",@file);  This script does not modify the file itself though. Some people pointed me that Perl was too much for this task. I have been told about Groff or Par to format my files. Finally, I found a very BARE way to handle this. As I write my text with ed, I added an new alias named “ruled” with spawn ed with a prompt of 70 characters #, so I have a rule each time ed displays its prompt!!! :D It looks like this for the last paragraph: ###################################################################### c been told about Groff or Par to format my files. Finally, I found a very **BARE** way to handle this. As I write my text with ed, I added an new alias named "ruled" with spawn ed with a prompt of 70 characters #, so I have a rule each time ed displays its prompt!!! :D . ###################################################################### w  Obviously, this way to proceed only works when writing the content at first. If I need to edit a paragraph, I will need a tool to format correctly my document again. ## Jabber client Using jabber inside Emacs is not a very good experience. I switched to profanity (featured some times ago on this blog). ## Playing Chess Well, I stopped playing chess by mails, I am still waiting for my recipient to play his turn since two years now. We were exchanging the notation of the whole play in each mail, by adding our turn each time, I was doing the rendering in Emacs, but I do not remember exactly why but I had problems with this (replaying the string). # Easy encrypted backups on OpenBSD with base tools Written by Solène, on 26 June 2018. Tags: #unix #openbsd Today’s topic is “Encrypted backups” using only OpenBSD base tools. I am planning to write a bigger article later about backups but it’s a wide topic with a lot of software to cover and a lot of explanations about the differents uses cases, needs, issues an solutions. Here I will stick on explaining how to make reliable backups for an OpenBSD system (my laptop). What we need is the dump command (see man 8 dump for its man page). It’s an utility to make a backup for a filesystem, it can only make a backup of one filesystem at a time. On my laptop I only backup /home partition so this solution is suitable for me while still being easy. Dump can do incremental backups, it means that it will only save what changed since the last backup of lower level. If you do not understand this, please refer to the dump man page. What is very interesting with dump is that it honors nodump flag which is an extended attribute of a FFS filesystem. One can use the command chflags nodump /home/solene/Downloads to tells dump not do save that folder (under some circumstances). By default, dump will not save thoses files, EXCEPT for a level 0 backup. Important features of this backup solution: • save files with attributes, permissions and flags • can recreate a partition from a dump, restore files interactively, from a list or from its inode number (useful when you have files in lost+found) • one dump = one file My process is to make a huge dump of level 0 and keep it on a remote server, then, once a week I make a level 1 backup which will contain everything changed since the last dump of level 0, and everyday I do a level 2 backup of my files. The level 2 will contain latest files and the files changing a lot, which are often the most interesting. The level 1 backup is important because it will offload a lot of changes for the level 2. Let me explain: let says my full backup is 60 GB, full of pictures, sources files, GUI applications data files etc… A level 1 backup will contain every new picture, new projects, new GUI files etc.. since the full backup, which will produce bigger and bigger dump over time, usually it is only 100 MB to 1GB. As I don’t add new pictures everyday or use new software everyday, the level 2 will take care of most littles changes to my data, like source code edited, little works on files etc… The level 2 backup is really small, I try to keep it under 50 MB so I can easily send it on my remote server everyday. One could you more dump level, up to level 9, but keep in mind that those are incremental. In my case, if I need to restore all my partition, I will need to use level 0, 1 and 2 to get up to latest backup state. If you want to restore a file deleted a few days ago, you need to remember in which level its latest version is. History note: dump was designed to be used with magnetic tapes. Now, the interesting part: how to use it? ## Commands to make a backup The process is the following: dump | compression | openssl > file To make a level 0 dump ignoring files having nodump flag: dump -0 -h0 -a -u -f - /home  This will output the dump to stdout and ignore nodump files below level 0, which will ignore it whatever the current level is. Now we will encrypt it with openssl to store securely the files on any media we could use (usb media, remote server, local server, another computer). We will use openssl command for this, with the password in the command line (this is not a problem for me as my computer is trustable). LEVEL=0 dump -${LEVEL} -h0 -a -u -f - /home | \
openssl enc -k "7H3_P@$$W0RD" -aes-256-cbc -salt -out dump-level{LEVEL}.enc  I choosed .enc extension file for encoded. You will need the password to read the file. Now, we will see that using a compression tool before openssl can save a lot of space (depending of your data though). It is really easy to add compress in this pipe command. LEVEL=0 dump -{LEVEL} -h0 -a -u -f - /home | \ gzip -f -c | \ openssl enc -k "7H3_P@$$W0RD" -aes-256-cbc -salt -out dump-level${LEVEL}.gz.enc  In this case, gzip will save a lot of space if like me, most of your disk usage are mails and text files. We can push the compression a little further as we want to reduce backup size for sending it to a remote server. We will use xz command with 2 threads to make it faster and disable checksum because anyway, openssl will allow to verify the integrity of the file. LEVEL=0 dump -${LEVEL} -h0 -a -u -f - /home | \
xz -C none -T 2 -f -c | \
openssl enc -k "7H3_P@$$W0RD" -aes-256-cbc -salt -out dump-level{LEVEL}.xz.enc  ## How to restore from a dump Now that we have a shiniy backup that we hope we will never have to use, it is important to understand to use it if needed. The process is the following: cat file | openssl | decompression | restore Before someone scream about the cat command, I know that I could use openssl file instead of but it feels more pleasant to read like this. cat dump-level0.gz.enc | \ openssl enc -d -k "7H3_P@$$W0RD" -aes-256-cbc -salt - | \
xz -d -T2 -f -c - | \
restore -i -f -


One could write a short script like the following to give the file as a parameter and allow to choose restore’s parameters.

FILE=$1 ; shift test -f "${FILE}" && cat "$1" | \ openssl enc -d -k "7H3_P@$$W0RD" -aes-256-cbc -salt - | \ xz -d -T2 -f -c - | \ restore$@ -f -


I have faced situations where restore should be called with differents flags, like -m to show inodes.

I hope you found this article interesting, I wanted to share a daily usage of simple tools which can give interesting features when combined together.

# Change default application for xdg-open

Written by Solène, on 25 June 2018.
Tags: #unix

I write it as a note for me and if it can helps some other people, it’s fine.

To change the program used by xdg-open for opening some kind of file, it’s not that hard.

First, check the type of the file:

$xdg-mime query filetype file.pdf application/pdf  Then, choose the right tool for handling this type: $ xdg-mime default mupdf.desktop application/pdf


Honestly, having firefox opening PDF files with GIMP IS NOT FUN.

# OpenBSD as an IPv6 router

Written by Solène, on 06 June 2018.
Tags: #openbsd #network

Yesterday I subscribed to a VPN service from the french association Grifon (Grifon website[FR] | gopher://grifon.fr) to get an IPv6 access to the world and play with IPv6. I will not talk about the VPN service in this article, it would be pointless.

So, I have an IPv6 prefix of 48 bytes which mean I can have a lot of addresses (I did some maths and found 655362 addresses but I am not sure about this).

Now, I would like my computer connected through the VPN to let others computers in my network to have IPv6 connectivity.

On OpenBSD, this only requires a few services, if you want to provide IPv6 to Windows devices on your network, you will need one more.

First, configure IPv6 on your lan

# ifconfig em0 inet6 autoconf


that’s all, you can add a new line “inet6 autoconf” to your file /etc/hostname.if to get it at boot.

Now, we have to allow IPv6 to be routed through the differents interfaces of the router.

# sysctl net.inet6.ip6.forwarding=1


This change can be made persistent across reboot by adding net.inet6.ip6.forwarding=1 to the file /etc/sysctl.conf.

Now we have to configure the daemon rtadvd to advertise the we are routing, devices on the network should be able to get an IPv6 address from its advertisement.

The minimal configuration of /etc/rtadvd.conf is the following:

em0:\


In this configuration file, you have to type your IPv6 prefix in the addr field, and the prefix length in prefixlen. Others attributes could provide DNS servers to use for example.

Then enable the service at boot and start it:

# rcctl enable rtadvd
# rcctl set rtadvd flags em0


### Tweaking resolv.conf

By default OpenBSD will ask for IPv4 when resolving a hostname (see syslog.conf(5) for more explanations). So, you will never have IPv6 traffic until you use a software which will request explicit IPv6 connection or that the hostname is only defined with a AAAA field.

# echo "family inet6 inet" >> /etc/resolv.conf.tail


The file resolv.conf.tail is appended at the end of resolv.conf when dhclient modifies the file resolv.conf.

### Microsoft Windows

If you have Windows systems on your network, they won’t get addresses from rtadvd. You will need to deploy dhcpv6 daemon.

The configuration file for what we want to achieve here is pretty simple, it consists of telling what range we want to allow on DHCPv6 and a DNS server. Create the file /etc/dhcp6s.conf:

interface em0 {
};
pool pool1 {
range 2a00:5414:7311:1111::1000 to 2a00:5414:7311:1111::4000;
};
option domain-name-servers 2001:db8::35;


Note that I added “1111” into the range because it should not be on the same network than the router.

Now, you have to install and configure the service:

# pkg_add wide-dhcpv6
# echo SOME_RANDOM_CHARACTERS | openssl enc -base64 > /etc/dhcp6sctlkey
# chmod 400 /etc/dhcp6sctlkey
# echo "dhcp6s -c /etc/dhcp6s.conf  em0" >> /etc/rc.local


The openbsd package wide-dhcpv6 doesn’t provide a rc file to start/stop the service so it must be started from a command line, a way to do it is to type the command in /etc/rc.local which is run at boot. The openssl part is mandatory for dhcpv6 to start, it requires a base64 string as a secret key in the file /etc/dhcp6sctlkey.

# Share a tmux session with someone with tmate

Written by Solène, on 01 June 2018.
Tags: #unix

New port of the week, and it’s about tmate.

If you ever wanted to share a terminal with someone without opening a remote access to your computer, tmate is the right tool for this.

Once started, tmate will create a new tmux instance connected through the tmate public server, by typing tmate show-messages you will get url for read-only or read-write links to share with someone, by ssh or web browser. Don’t forget to type clear to hide url after typing show-messages, otherwise viewing people will have access to the write url (and it’s not something you want).

If you don’t like the need of a third party, you can setup your own server, but we won’t cover this in this article.

When you want to end the share, you just need to exit the tmux opened by tmate.

If you want to install it on OpenBSD, just type pkg_add tmate and you are done. I think it’s available on most unix systems.

There is no much more to say about it, it’s great, simple, work out-of-the-box with no configuration needed.

# Deploying cron programmaticaly the unix way

Written by Solène, on 31 May 2018.
Tags: #unix

Here is a little script to automatize in some way your crontab deployment when you don’t want to use a configuration tool like ansible/salt/puppet etc…

The script works this way:

./install_cron crontab_solene


with crontab_solene file being an actual crontab correct, which could looks like this:

## TAG ##
MAILTO=""
*/5 * * * *  ( cd ~/dev/reed-alert && ecl --load check.lisp )
*/10 * * * * /usr/local/bin/r2e run
1 * * * * vacuumdb -azf -U postgres
## END_TAG ##


Then it will include the file into my current user crontab, the TAG in the file is here to be able to remove it and replace it later with the new version. The script could be easily modified to support the tag name as parameter, if you have multiple deploymenets using the same user on the same machine.

#!/bin/sh

if [ -z "$1" ]; then echo "Usage:$0 user_crontab_file"
exit 1
fi

VALIDATION=0
grep "^## TAG ##$" "$1" >/dev/null
VALIDATION=$? grep "^## END_TAG ##$" "$1" >/dev/null VALIDATION=$(( VALIDATION + $? )) if [ "$VALIDATION" -ne 0 ]
then
echo "file ./${1} needs \"## TAG ##\" and \"## END_TAG ##\" to be used" exit 2 fi crontab -l | \ awk '{ if($0=="## TAG ##") { hide=1 };  if(hide==0) { print } ; if($0=="## END_TAG ##") { hide=0 }; }' | \ cat - "${1}" | \
crontab -


# Mount a folder on another folder

Written by Solène, on 22 May 2018.
Tags: #openbsd

This article will explain quickly how to bind a folder to access it from another path. It can be useful to give access to a specific folder from a chroot without moving or duplicating the data into the chroot.

Real world example: “I want to be able to access my 100GB folder /home/my_data/ from my httpd web server chrooted in /var/www/”.

The trick on OpenBSD is to use NFS on localhost. It’s pretty simple.

# rcctl enable portmap nfsd mountd
# echo "/home/my_data -network=127.0.0.0 -mask=255.255.255.0" > /etc/exports
# rcctl start portmap nfsd mountd


The order is really important. You can check that the folder is available through NFS with the following command:

$showmount -e Exports list on localhost: /home/my_data loopback  If you don’t have any line after “Exports list on localhost:”, you should kill mountd with pkill -9 mountd and start mountd again. I experienced it twice when starting all the daemons from the same commands but I’m not able to reproduce it. By the way, mountd only supports reload. If you modify /etc/exports, you only need to reload mountd using rcctl reload mountd. Once you have check that everything was alright, you can mount the exported folder on another folder with the command: # mount localhost:/home/my_data /var/www/htdocs/my_data  You can add -ro parameter in the /etc/exports file on the export line if you want it to be read-only where you mount it. Note: On FreeBSD/DragonflyBSD, you can use mount_nullfs /from /to, there is no need to setup a local NFS server. And on Linux you can use mount --bind /from /to and some others ways that I won’t cover here. # Faster SSH with multiplexing Written by Solène, on 22 May 2018. Tags: #unix #ssh I discovered today an OpenSSH feature which doesn’t seem to be widely known. The feature is called multiplexing and consists of reusing an opened ssh connection to a server when you want to open another one. This leads to faster connection establishment and less processes running. To reuse an opened connection, we need to use the ControlMaster option, which requires ControlPath to be set. We will also set ControlPersist for convenience. • ControlMaster defines if we create, or use or nothing about multiplexing • ControlPath defines where to store the socket to reuse an opened connection, this should be a path only available to your user. • ControlPersist defines how much time to wait before closing a ssh connection multiplexer after all connection using it are closed. By default it’s “no” and once you drop all connections the multiplexer stops. I choosed to use the following parameters into my ~/.ssh/config file: Host * ControlMaster auto ControlPath ~/.ssh/sessions/%h%p%r.sock ControlPersist 60  This requires to have ~/.ssh/sessions/ folder restricted to my user only. You can create it with the following command: install -d -m 700 ~/.ssh/sessions  (you can also do mkdir ~/.ssh/sessions && chmod 700 ~/.ssh/sessions but this requires two commands) The ControlPath variable will creates sessions with the name “${hostname}${port}${user}.sock”, so it will be unique per remote server.

Finally, I choose to use ControlPersist to 60 seconds, so if I logout from a remote server, I still have 60 seconds to reconnect to it instantly.

Don’t forget that if for some reason the ssh channel handling the multiplexing dies, all the ssh connections using it will die with it.

## Benefits with ProxyJump

Another ssh feature that is very useful is ProxyJump, it’s really useful to access ssh hosts which are not directly available from your current place. Like servers with no public ssh server available. For my job, I have a lot of servers not facing the internet, and I can still connect to them using one of my public facing server which will relay my ssh connection to the destination. Using the ControlMaster feature, the ssh relay server doesn’t have to handle lot of connections anymore, but only one.

In my ~/.ssh/config file:

Host *.private.lan
ProxyJump public-server.com


Those two lines allow me to connect to every servers with .private.lan domains (which is known by my local DNS server) by typing ssh some-machine.private.lan. This will establish a connection to public-server.com and then connects to the next server.

# Sending mail with mu4e

Written by Solène, on 22 May 2018.
Tags: #unix #emacs

In my article about mu4e I said that I would write about sending mails with it. This will be the topic covered in this article.

There are a lot of ways to send mails with a lot of differents use cases. I will only cover a few of them, the documentation of mu4e and emacs are both very good, I will only give hints about some interestings setups.

I would thank Raphael who made me curious about differents ways of sending mails from mu4e and who pointed out some mu4e features I wasn’t aware of.

## Send mails through your local server

The easiest way is to send mails through your local mail server (which should be OpenSMTPD by default if you are running OpenBSD). This only requires the following line to works in your ~/.emacs file:

(setq message-send-mail-function 'sendmail-send-it)


Basically, it would be only relayed to the recipient if your local mail is well configured, which is not the case for most servers. This requires a reverse DNS address correctly configured (assuming a static IP address), a SPF record in your DNS and a DKIM signing for outgoing mail. This is the minimum to be accepted to others SMTP servers. Usually people send mails from their personal computer and not from the mail server.

### Configure OpenSMTPD to relay to another smtp server

We can bypass this problem by configuring our local SMTP server to relay our mails sent locally to another SMTP server using credentials for authentication.

This is pretty easy to set-up, by using the following /etc/mail/smtpd.conf configuration, just replace remoteserver by your server.

table aliases file:/etc/mail/aliases
table secrets file:/etc/mail/secrets

listen on lo0

accept for local alias <aliases> deliver to mbox
accept for any relay via secure+auth://label@remoteserver:465 auth <secrets>


You will have to create the file /etc/mail/secrets and add your credentials for authentication on the SMTP server.

From smtpd.conf(5) man page, as root:

# touch /etc/mail/secrets
# chmod 640 /etc/mail/secrets
# chown root:_smtpd /etc/mail/secrets


Then, all mail sent from your computer will be relayed through your mail server. With ’sendmail-send-it, emacs will delivered the mail to your local server which will relay it to the outgoing SMTP server.

## SMTP through SSH

One setup I like and I use is to relay the mails directly to the outgoing SMTP server, this requires no authentication except a SSH access to the remote server.

It requires the following emacs configuration in ~/.emacs:

(setq
message-send-mail-function 'smtpmail-send-it
smtpmail-smtp-server "localhost"
smtpmail-smtp-service 2525)


The configuration tells emacs to connect to the SMTP server on localhost port 2525 to send the mails. Of course, no mail daemon runs on this port on the local machine, it requires the following ssh command to be able to send mails.

$touch ~/Mail/queue/.noindex  Then, mu4e will be aware of the queueing, in the home screen of mu4e, you will be able to switch from queuing to direct sending by pressing m and flushing the queue by pressing f. Note: there is a bug (not sure it’s really a bug). When sending a mail into the queue, if your mail contains special characters, you will be asked to send it raw or to add a header containing the encoding. # Autoscrolling text for lazy reading Written by Solène, on 17 May 2018. Tags: #unix Today I found a software named Lazyread which can read and display file an autoscroll at a chosen speed. I had to read its source code to make it work, the documentation isn’t very helpful, it doesn’t read ebooks (as in epub or mobi format) and doesn’t support stdin… This software requires some C code + a shell wrapper to works, it’s complicated for only scrolling. So, after thinking a few minutes, the autoscroll can be reproduced easily with a very simple awk command. Of course, it will not have the interactive keys like lazyread to increase/decrease speed or some others options, but the most important part is there: autoscrolling. If you want to read a file with a rate of 1 line per 700 millisecond, just type the following command: awk '{system("sleep 0.7");print}' file  Do you want to read an html file (documentation file on the disk or from the web), you can use lynx or w3m to convert the html file on the fly to a readable text and pass it to awk stdin. w3m -dump doc/slsh/slshfun-2.html | awk '{system("sleep 0.7");print}' lynx -dump doc/slsh/slshfun-2.html | awk '{system("sleep 0.7");print}' w3m -dump https://dataswamp.org/~solene/ | awk '{system("sleep 0.7");print}'  Maybe you want to read a man page? man awk | awk '{system("sleep 0.7");print}'  If you want to pause the reading, you can use the true unix way, Ctrl+Z to send a signal which will stop the command and let it paused in background. You can resume the reading by typing fg. One could easily write a little script parsing parameters for setting the speed or handling files or url with the correct command. Notes: If for some reasons you try to use lazyread, fix the shebang in the file lesspipe.sh and you will need to call lazyread binary with the environment variable LESSOPEN="|./lesspipe.sh %s" (the path of the script if needed). Without this variable, you will have a very helpful error “file not found”. # Port of the week: Sent Written by Solène, on 15 May 2018. Tags: #unix As the new port of the week, We will discover Sent. While we could think it is mail related, it is not. Sent is a nice software to make presentations from a simple text file. It has been developped by Suckless, a hacker community enjoying writing good software while keeping a small and sane source code, they also made software like st, dwm, slock, surf… Sent is about simplicity. I will reuse a part of the example file which is also the documentation of the tool. usage:$ sent FILE1 [FILE2 …]

▸ one slide per paragraph
▸ lines starting with # are ignored
▸ image slide: paragraph containing @FILENAME
▸ empty slide: just use a \ as a paragraph

@nyan.png
this text will not be displayed, since the @ at the start of the first line
makes this paragraph an image slide.


The previous text, saved into a file and used with sent will open a fullscreen window containg three “slides”. Each slide will resize the text to maximize the display usage, this mean the font size will change on each slide.

It is really easy to use. To display next slide, you have the choice between pressing space, right arrow, return or clicking any button. Pressing left arrow will go back.

If you want to install it on OpenBSD: pkg_add sent, the package comes from the port misc/sent.

Be careful, Sent does not produce any file, you will need it for the presentation!

Suckless sent website

# Use ramdisk on /tmp on OpenBSD

Written by Solène, on 08 May 2018.
Tags: #openbsd

If you have enough memory on your system and that you can afford to use a few hundred megabytes to store temporary files, you may want to mount a mfs filesystem on /tmp. That will help saving your SSD drive, and if you use an old hard drive or a memory stick, that will reduce your disk load and improve performances. You may also want to mount a ramdisk on others mount points like ~/.cache/ or a database for some reason, but I will just explain how to achieve this for /tmp with is a very common use case.

First, you may have heard about tmpfs, but it has been disabled in OpenBSD years ago because it wasn’t stable enough and nobody fixed it. So, OpenBSD has a special filesystem named mfs, which is a FFS filesystem on a reserved memory space. When you mount a mfs filesystem, the size of the partition is reserved and can’t be used for anything else (tmpfs, as the same on Linux, doesn’t reserve the memory).

Add the following line in /etc/fstab (following fstab(5)):

swap /tmp mfs rw,nodev,nosuid,-s=300m 0 0


# Mounting remote samba share through SSH tunnel

Written by Solène, on 04 May 2018.
Tags: #unix

If for some reason you need to access a Samba share outside of the network, it is possible to access it through ssh and mount the share on your local computer.

Using the ssh command as root is required because you will bind local port 139 which is reserved for root:

# ssh -L 139:127.0.0.1:139 user@remote-server -N


Then you can mount the share as usual but using localhost instead of remote-server.

Example of a mount element for usmb

<mount id="public" credentials="me">
<server>127.0.0.1</server>
<!--server>192.168.12.4</server-->
<share>public</share>
<mountpoint>/mnt/share</mountpoint>
<options>allow_other,uid=1000</options>
</mount>


As a reminder, <!--tag>foobar</tag--> is a XML comment.

# Extract files from winmail.dat

Written by Solène, on 02 May 2018.
Tags: #unix #email

If you ever receive a mail with an attachment named “winmail.dat” then may be disappointed. It is a special format used by Microsoft Exchange, it contains the files attached to the mail and need some software to extract them.

Hopefully, there is a little and effecient utility named “tnef” to extract the files.

Install it: pkg_add tnef

List files: tnef -t winmail.dat

Extract files: tnef winmail.dat

That’s all !

# Port of the week : ledger

Written by Solène, on 02 May 2018.
Tags: #unix

In this post I will do a short presentation of the port productivity/ledger, an very powerful command line accounting software, using plain text as back-end. Writing on it is not an easy task, I will use a real life workflow of my usage as material, even if my use is special.

As I said before, Ledger is very powerful. It can helps you manage your bank accounts, bills, rents, shares and others things. It uses a double entry system which means each time you add an operation (withdraw, paycheck, …) , this entry will also have to contain the current state of the account after the operation. This will be checked by ledger by recalculating every operations made since it has been initialized with a custom amount as a start. Ledger can also tracks categories where you spend money or statistics about your payment method (check, credit card, bank transfer, money…).

As I am not an english native speaker and that I don’t work in banks or related, I am not very familiar with accounting words in english, it makes me very hard to understand all ledger keywords, but I found a special use case for accounting things and not money which is really practical.

My special use case is that I work from home for a company working in a remote location. From time to time, I take the train to the to the office, the full travel is

[home]   → [underground A] → [train] → [underground B] → [office]
[office] → [underground B] → [train] → [underground A] → [home]


It means I need to buy tickets for both underground A and underground B system, and I want to track tickets I use for going to work. I buy the tickets 10 by 10 but sometimes I use it for my personal use or sometimes I give a ticket to someone. So I need to keep track of my tickets to know when I can give a bill to my work for being refunded.

Practical example: I buy 10 tickets of A, I use 2 tickets at day 1. On day 2, I give 1 ticket to someone and I use 2 tickets in the day for personal use. It means I still have 5 tickets in my bag but, from my work office point of view, I should still have 8 tickets. This is what I am tracking with ledger.

2018/02/01 * tickets stock Initialization + go to work
Tickets:inv                                   10 City_A
Tickets:inv                                   10 City_B
Tickets:inv                                   -2 City_A
Tickets:inv                                   -2 City_B
Tickets

2018/02/08 * Work
Tickets:inv                                    -2 City_A
Tickets:inv                                    -2 City_B
Tickets

2018/02/15 * Work + Datacenter access through underground
Tickets:inv                                    -4 City_B
Tickets:inv                                    -2 City_A
Tickets


At the point, running ledger -f tickets.dat balance Tickets shows my tickets remaining:

4 City_A
2 City_B  Tickets:inv


2018/02/22 * Work + Datacenter access through underground
Tickets:inv                                    -4 City_B
Tickets:inv                                    -2 City_A
Tickets:inv                                    10 City_B
Tickets


Now, running ledger -f tickets.dat balance Tickets shows my tickets remaining:

2 City_A
8 City_B  Tickets:inv


I hope that the example was clear enought and interesting. There is a big tutorial document available on the ledger homepage, I recommend to read it before using ledger, it contains real world examples with accounting. Homepage link

# Port of the week : dnstop

Written by Solène, on 18 April 2018.
Tags: #unix

Dnstop is an interactive console application to watch in realtime the DNS queries going through a network interface. It currently only supports UDP DNS requests, the man page says that TCP isn’t supported.

It has a lot of parameters and keybinding for the interactive use

To install it on OpenBSD: doas pkg_add dnstop

We will start dnstop on the wifi interface using a depth of 4 for the domain names: as root type dnstop -l 4 iwm0 and then press ‘3’ to display up to 3 sublevel, the -l 4 parameter means we want to know domains with a depth of 4, it means that if a request for the domain my.very.little.fqdn.com. happens, it will be truncated as very.little.fqdn.com. If you press ‘2’ in the interactive display, the earlier name will be counted in the line fqdn.com’.

Example of output:

Queries: 0 new, 6 total                           Tue Apr 17 07:17:25 2018

Query Name          Count      %   cum%
--------------- --------- ------ ------
perso.pw                3   50.0   50.0
foo.bar                 1   16.7   66.7
hello.mydns.com         1   16.7   83.3
mydns.com.lan           1   16.7  100.0


If you want to use it, read the man page first, it has a lot of parameters and can filters using specific expressions.

# How to read a epub book in a terminal

Written by Solène, on 17 April 2018.
Tags: #unix

If you ever had to read an ebook in a epub format, you may have find yourself stumbling on Calibre software. Personally, I don’t enjoy reading a book in Calibre at all. Choice is important and it seems that Calibre is the only choice for this task.

But, as the epub format is very simple, it’s possible to easily read it with any web browser even w3m or lynx.

With a few commands, you can easily find xhtml files that can be opened with a web browser, an epub file is a zip containing mostly xhtml, css and images files. The xhtml files have links to CSS and images contained in others folders unzipped.

In the following commands, I prefer to copy the file in a new directory because when you will unzip it, it will create folder in your current working directory.

$mkdir /tmp/myebook/$ cd /tmp/myebook
$cp ~/book.epub .$ unzip book.epub
$cd OPS/xhtml$ ls *xhtml


I tried with differents epub files, in most case you should find a lot of files named chapters-XX.xhtml with XX being 01, 02, 03 and so forth. Just open the files in the correct order with a web browser aka “html viewer”.

# Port of the week : tig

Written by Solène, on 10 April 2018.
Tags: #unix #git

Today we will discover the software named tig whose name stands for Text-mode Interface for Git.

To install it on OpenBSD: pkg_add tig

Tig is a light and easy to use terminal application to browse a git repository in an interactive manner. To use it, just ‘cd’ into a git repository on your filesystem and type tig. You will get the list of all the commits, with the author and the date. By pressing “Enter” key on a commit, you will get the diff. Tig also displays branching and merging in a graphical way.

Tig has some parameters, one I like a lot if blame which is used like this: tig blame afile. Tig will show the file content and will display for each line to date of last commit, it’s author and the small identifier of the commit. With this function, it gets really easy to find who modified a line or when it was modified.

Tig has a lot of others possibilities, you can discover them in its man pages.

# Unofficial OpenBSD FAQ

Written by Solène, on 16 March 2018.
Tags: #openbsd

I am writing this to answer questions asked too many times. If some answers get good enough, maybe we could try to merge it in the OpenBSD FAQ if the topic isn’t covered. If the topic is covered, then a link to the official FAQ should be used.

If you want to participate, you can fetch the page using gopher protocol and send me a diff:

$printf '/~solene/article-openbsd-faq.txt\r\n' | nc dataswamp.org 70 > faq.md  ## What is the OpenBSD release process? OpenBSD FAQ official information The last two releases are called “-release” and are officially supported (patches for security issues are provided). -stable version is the latest release with the base system patches applied, the -stable ports tree has some patches backported from -current, mainly to fix security issues. Official packages are not built for -stable. You have to build them yourself or install them using a third party service like M:Tier ## What is -current? It’s the development version with latest packages and latest code. You shouldn’t use it only to get latest package versions. ## How do I install -current ? OpenBSD FAQ about current • download the latest snapshot install .iso or .fs file from your favorite mirror under /snapshots/ directory • boot from it ## How do I upgrade to -current OpenBSD FAQ about current • download the latest bsd.rd file from your favorite mirror • verify its checksum and signature using signify and SHA256.sig file • rename the old ramdisk kernel as /bsd.rd.old just in case • copy the ramdisk kernel in its place - /bsd.rd • reboot • type “boot bsd.rd” at bootloader prompt • choose “U” to upgrade • reboot after the upgrade process • pkg_add -u to update your packages Repeat in order to upgrade to a newer -current snapshot ## How do I update packages on my release version ? Packages are frozen at the release and not updated. # Monitor your systems with reed-alert Written by Solène, on 17 January 2018. Tags: #unix #monitoring #lisp This article will present my software reed-alert, it checks user-defined states and send user-defined notification. I made it really eay to use but still configurable and extensible. ## Description reed-alert is not a monitoring tool producing graph or storing values. It does a job sysadmins are looking for because there are no alternative product (the alternatives comes from a very huge infrastructure like Zabbix so it’s not comparable). From its configuration file, reed-alert will check various states and then, if it fails, will trigger a command to send a notification (totally user-defined). ## Fetch it This is a open-source and free software released under MIT license, you can get it with the following command: git clone git://bitreich.org/reed-alert cd reed-alert  A README file is available as documentation to describe how to use it, but we will see here how to get started quickly. You will find a few files there, reed-alert is a Common LISP software and it has been choosed for (I hope) good reasons that the configuration file is plain Common LISP. There is a config file looking like a real world example named config.lisp.sample and another configuration file I use for testing named example.lisp containing lot of cases. ## Let’s start In order to use reed-alert we only need to create a new configuration file and then add a cron job. ### Configuration We are going to see how to configure reed-alert. You can find more explanations or details in the README file. #### Alerts We have to configure two kind of parameters, first we need to set-up a way to receive alerts, easiest way to do so is by sending a mail with “mail” command. Alerts are declared with the function alert and as parameters the alert name and the command to be executed. Some variables are replaced with values from the probe, in the README file you can find the list of probes, it looks like %date% or %params%. In Common LISP functions are called by using a parenthesis before its name and until the parenthesis is closed, we are giving its parameters. Example: (alert mail "echo 'problem on %hostname%' | mail me@example.com")  One should take care about nesting quotes here. reed-alert will fork a shell to start the command, so pipes and redirections works. You can be creative when writing alerts that: • use a SMS service • write a script to post on a forum • publishing a file on a server • send text to irc with ii client #### Checks Now we have some alerts, we will configure some checks in order to make reed-alert useful. It uses probes which are pre-defined checks with parameters, a probe could be “has this file not been updated since N minutes ?” or “Is the disk space usage of partition X more than Y ?” I choosed to name the function “=>” to make a check, it isn’t a name and reminds an item or something going forward. Both previous example using our previous mail notifier would look like: (=> mail file-updated :path "/program/file.generated" :limit "10") (=> mail disk-usage :limit 90)  It’s also possible to use shell commands and check the return code using the command probe, allowing the user to define useful checks. (=> mail command :command "echo '/is-this-gopher-server-up?' | nc -w 3 dataswamp.org 70" :desc "dataswamp.org gopher server")  We use echo + netcat to check if a connection to a socket works. The :desc keyword will give a nicer name in the output instead of just “COMMAND”. #### Garniture We wrote the minimum required to configure reed-alert, now the configuration file requires only two more lines, so your my-config.lisp file should looks like the following: (load "functions.lisp") (alert mail "echo 'problem on %hostname%' | mail me@example.com") (=> mail file-updated :path "/program/file.generated" :limit "10") (=> mail disk-usage :limit 90) (quit)  The first line is mandatory to make things working, the last line will prevent the lisp interpreter to stay in REPL (user interactive input). Now, you can start it every 5 minutes from a crontab with this: */5 * * * * ( cd /home/user/projects/reed-alert/ ; sbcl --load my-config.lisp )  If you prefer to use ecl: */5 * * * * ( cd /home/user/projects/reed-alert/ ; ecl --load my-config.lisp )  The time between each run is up to you, depending on what you monitor. #### Important By default, when a check returns a failure, reed-alert will only trigger the notifier associated once it reach the 3rd failure. And then, will notify again when the service is back (the variable %state% is replaced by start or end to know if it starts or stops.) This is to prevent reed-alert to send a notification each time it checks, there is absolutely no need for this for most users. The number of failures before triggering can be modified by using the keyword “:try” as in the following example: (=> mail disk-usage :limit 90 :try 1)  In this case, you will get notified at the first failure of it. The number of failures of failed checks is stored in files (1 per check) in the “states/” directory of reed-alert working directory. # New cl-yag version Written by Solène, on 16 December 2017. Tags: #unix ## Introduction cl-yag is a static website generator. It's a software used to publish a website and/or a gopher hole from a list of articles. As the developer of cl-yag I'm happy to announce that a new version has been released. ## New features The new version, with its number 0.6, bring lot of new features : • supporting different markup language per article • date format configurable • gopher output format configurable • ship with the default theme "clyma", minimalist but responsive (the one used on this website) • easier to use • full user documentation The code is available at git://bitreich.org/cl-yag, the program requires sbcl or ecl to work. ### Per article markup language The best feature I'm proud of is allowing to use a different language per article. While on my blog I choosed to use markdown, it's sometimes not adapted for more elaborated articles like the one about LISP containing code which was written in org-mode then converted to markdown manually to fit to cl-yag. Now, the user can declare a named "converter" which is a command line with pattern replacement, to produce the html file. We can imagine a lot of things with this, even producing a gallery with find + awk command. Now, I can use markdown by default and specify if I want to use org-mode or something else. This is the way to declare a converter, taking org-mode as example, which is not very simple, because of emacs not being script friendly : (converter :name :org-mode :extension ".org" :command (concatenate 'string "emacs data/%IN --batch --eval '(with-temp-buffer (org-mode) " "(insert-file \"%IN\") (org-html-export-as-html nil nil nil t)" "(princ (buffer-string)))' --kill | tee %OUT"))  And an easy way to produce a gallery with awk from a .txt file containing a list of images path. (converter :name :gallery :extension ".txt" :command (concatenate 'string "awk 'BEGIN { print \"<div class=\\\"gallery\\\">\"} " "{ print \"<img src=\\\"static/images/\"$1\"\\\" />\" } "
" END { print  \"</div>\"} data/%IN | tee %OUT"))


The concatenate function is only used to improve the presentation, to split the command in multiples lines and make it easier to read. It's possible to write all the command in one line.

The patterns %IN and %OUT are replaced by the input file name and the output file name when the command is executed.

For an easier example, the default markdown converter looks like this, calling multimarkdown command :

(converter :name :markdown :extension ".md"
:command "multimarkdown -t html -o %OUT data/%IN")


It's really easy (I hope !) to add new converters you need with this feature.

### Date format configurable

One problem I had with cl-yag is that it's plain vanilla Common LISP without libraries, so it's easier to fetch and use but it lacks some elaborated libraries like one to parse date and format a date. Before this release, I was writing in plain text "14 December 2017" in the date field of a blog post. It was easy to use, but not really usable in the RSS feed in the pubDate attribute, and if I wanted to change the display of the date for some reason, I would have to rewrite everything.

Now, the date is simply in the format "YYYYMMDD" like "20171231" for the 31rd December 2017. And in the configuration variable, there is a :date-format keyword to define the date display. This variable is a string allowing pattern replacement of the following variables :

%DayNumber
day of the month in number, from 1 to 31
%DayName
day of the week, from Monday to Sunday, names are written in english in the source code and can be translated
%MonthNumber
month in number, from 1 to 12
%MonthName
month name, from January to December, names are written in english in the source code and can be translated
%Year
year

Currently, as the time of writing, I use the value "%DayNumber %MonthName %Year"

A :gopher-format keyword exist in the configuration file to configure the date format in the gopher export. It can be different from the html one.

### More Gopher configuration

There are cases where the gopher server use an unusual syntax compared to most of the servers. I wanted to make it configurable, so the user could easily use cl-yag without having to mess with the code. I provide the default for geomyidae and in comments another syntax is available. There is also a configurable value to indicates where to store the gopher page menu, it's not always gophermap, it could be index.gph or whatever you need.

### Easier to use

A comparison of code will make it easier to understand. There was a little change the way blog posts are declared :

From

(defparameter *articles*
(list
(list :id "third-article"  :title "My third article" :tag "me" :date "20171205")
(list :id "second-article" :title "Another article"  :tag "me" :date "20171204")
(list :id "first-article"  :title "My first article" :tag "me" :date "20171201")
))


to

(post :id "third-article"  :title "My third article" :tag "me" :date "20171205")
(post :id "second-article" :title "Another article"  :tag "me" :date "20171204")
(post :id "first-article"  :title "My first article" :tag "me" :date "20171201")


Each post are independtly declared and I plan to add a "page" function to create static pages, but this is going to be for the next version !

## Future work

I am very happy to hack on cl-yag, I want to continue improving it but I should really think about each feature I want to add. I want to keep it really simple even if it limits the features.

I want to allow the creation of static pages like "About me", "Legal" or "websites I liked" that integrates well in the template. The user may not want all the static pages links to go at the same place in the template, or use the same template. I'm thinking about this.

Also, I think the gopher generation could be improved, but I still have no idea how.

Others themes may come in the default configuration, allowing the user to have a choice between themes. But as for now, I don't plan to bring a theme using javascript.

# How to merge changes with git when you are a noob

Written by Solène, on 13 December 2017.
Tags: #git

I’m very noob with git and I always screw everything when someone clone one of my repo, contributes and asks me to merge the changes.

Now I found an easy way to merge commits from another repository. Here is a simple way to handle this. We will get changes from project1_modified to merge it into our project1 repository. This is not the fastest way or maybe not the optimal way, but I found it to work reliabily.

$cd /path/to/projects$ git clone git://remote/project1_modified
$cd my_project1$ git checkout master
$git remote add modified ../project1_modified/$ git remote update
$git checkout -b new_code$ git merge modified/master
$git checkout master$ git merge new_code
$git branch -d new_code  This process will makes you download the repository of the people who contributed to the code, then you add it as a remote sources into your project, you create a new branch where you will do the merge, if something is wrong you will be able to manage conflicts easily. Once you tried the code and you are fine, you need to merge this branch to master and then, when you are done, you can delete the branch. If later you need to get new commits from the other repo, it become easier. $ cd /path/to/projects
$cd project1_modified$ git pull
$cd ../my_project1$ git pull modified
$git merge modified/master  And you are done ! # How to type using only one hand : keyboard mirroring Written by Solène, on 12 December 2017. Tags: #unix Hello Today is a bit special because I’m writing with a mirror keyboard layout. I use only half my keyboard to type all characters. To make things harder, the layout is qwerty while I use azerty usually (I’m used to qwerty but it doesn’t help). Here, “caps lock” is a modifier key that must be pressed to obtain characters of the other side. As a mirror, one will find ‘p’ instead of ‘q’ or ‘h’ instead of ‘g’ while pressing caps lock. It’s even possible to type backspace to delete characters or to achieve a newline. All the punctuation isn’t available throught this, only ‘.<|¦>’",’. While I type this I get a bit faster and it become more and more easier. It’s definitely worth if you can’t use hands two. This a been made possible by Randall Munroe. To enable it just download the file Here and type xkbcomp mirrorlayout.kbd$DISPLAY


backspace is use with tilde and return with space, using the modifier of course.

I’ve spent approximately 15 minutes writing this, but the time spent hasn’t been linear, it’s much more fluent now !

Mirrorboard: A one-handed keyboard layout for the lazy by Randall Munroe

# Showing some Common Lisp features

Written by Solène, on 05 December 2017.
Tags: #lisp

# Introduction: comparing LISP to Perl and Python

We will refer to Common LISP as CL in the following article.

I wrote it to share what I like about CL. I’m using Perl to compare CL features. I am using real world cases for the average programmer. If you are a CL or perl expert, you may say that some example could be rewritten with very specific syntax to make it smaller or faster, but the point here is to show usual and readable examples for usual programmers.

This article is aimed at people with programming interest, some basis of programming knowledge are needed to understand the following. If you know how to read C, Php, Python or Perl it should be enough. Examples have been choosed to be easy.

I thank my friend killruana for his contribution as he wrote the python code.

## Variables

### Scope: global

Common Lisp code

(defparameter *variable* "value")


Defining a variable with defparameter on top-level (= outside of a function) will make it global. It is common to surround the name of global variables with \* character in CL code. This is only for readability for the programmer, the use of \* has no incidence.

Perl code

my $variable = "value";  Python code variable = "value";  ### Scope: local This is where it begins interesting in CL. Declaring a local variable with let create a new scope with parenthesis where the variable isn’t known outside of it. This prevent doing bad things with variables not set or already freed. let can define multiple variables at once, or even variables depending on previously declared variables using let\* Common Lisp code (let ((value (http-request))) (when value (let* ((page-title (get-title value)) (title-size (length page-title))) (when page-title (let ((first-char (subseq page-title 0 1))) (format t "First char of page title is ~a~%" first-char))))))  Perl code { local$value = http_request;
if($value) { local$page_title = get_title $value; local$title_size = get_size $page_title; if($page_title) {
local $first_char = substr$page_title, 0, 1;
printf "First char of page title is %s\n", $first_char; } } }  The scope of a local value is limited to the parent curly brakets, of a if/while/for/foreach or plain brakets. Python code if True: hello = 'World' print(hello) # displays World  There is no way to define a local variable in python, the scope of the variable is limited to the parent function. ## Printing and format text CL has a VERY powerful function to print and format text, it’s even named format. It can even manage plurals of words (in english only) ! Common Lisp code (let ((words (list "hello" "Dave" "How are you" "today ?"))) (format t "~{~a ~}~%" words))  format can loop over lists using ~{ as start and ~} as end. Perl code my @words = @{["hello", "Dave", "How are you", "today ?"]}; foreach my$element (@words) {
printf "%s ", $element; } print "\n";  Python code # Printing and format text # Loop version words = ["hello", "Dave", "How are you", "today ?"] for word in words: print(word, end=' ') print() # list expansion version words = ["hello", "Dave", "How are you", "today ?"] print(*words)  ## Functions ### function parameters: rest Sometimes we need to pass to a function a not known number of arguments. CL supports it with &rest keyword in the function declaration, while perl supports it using the @_ sigil. Common Lisp code (defun my-function(parameter1 parameter2 &rest rest) (format t "My first and second parameters are ~a and ~a.~%Others parameters are~%~{ - ~a~%~}~%" parameter1 parameter2 rest)) (my-function "hello" "world" 1 2 3)  Perl code sub my_function { my$parameter1 = shift;
my $parameter2 = shift; my @rest = @_; printf "My first and second parameters are %s and %s.\nOthers parameters are\n",$parameter1, $parameter2; foreach my$element (@rest) {
printf "    - %s\n", $element; } } my_function "hello", "world", 0, 1, 2, 3;  Python code def my_function(parameter1, parameter2, *rest): print("My first and second parameters are {} and {}".format(parameter1, parameter2)) print("Others parameters are") for parameter in rest: print(" - {}".format(parameter)) my_function("hello", "world", 0, 1, 2, 3)  The trick in python to handle rests arguments is the wildcard character in the function definition. ### function parameters: named parameters CL supports named parameters using a keyword to specify its name. While it’s not at all possible on perl. Using a hash has parameter can do the job in perl. CL allow to choose a default value if a parameter isn’t set, it’s harder to do it in perl, we must check if the key is already set in the hash and give it a value in the function. Common Lisp code (defun my-function(&key (key1 "default") (key2 0)) (format t "Key1 is ~a and key2 (~a) has a default of 0.~%" key1 key2)) (my-function :key1 "nice" :key2 ".Y.")  There is no way to pass named parameter to a perl function. The best way it to pass a hash variable, check the keys needed and assign a default value if they are undefined. Perl code sub my_function { my$hash = shift;

if(! exists $hash->{key1}) {$hash->{key1} = "default";
}

if(! exists $hash->{key2}) {$hash->{key2} = 0;
}

printf "My key1 is %s and key2 (%s) default to 0.\n",
$hash->{key1},$hash->{key2};
}

my_function { key1 => "nice", key2 => ".Y." };


Python code

def my_function(key1="default", key2=0):
print("My key1 is {} and key2 ({}) default to 0.".format(key1, key2))

my_function(key1="nice", key2=".Y.")


## Loop

CL has only one loop operator, named loop, which could be seen as an entire language itself. Perl has do while, while, for and foreach.

### loop: for

Common Lisp code

(loop for i from 1 to 100
do
(format t "Hello ~a~%" i))


Perl code

for(my $i=1;$i <= 100; $i++) { printf "Hello %i\n"; }  Python code for i in range(1, 101): print("Hello {}".format(i))  ### loop: foreach Common Lisp code (let ((elements '(a b c d e f))) (loop for element in elements counting element into count do (format t "Element number ~s : ~s~%" count element)))  Perl code # verbose and readable version my @elements = @{['a', 'b', 'c', 'd', 'e', 'f']}; my$count = 0;
foreach my $element (@elements) {$count++;
printf "Element number %i : %s\n", $count,$element;
}

# compact version
for(my $i=0;$i<$#elements+1;$i++) {
printf "Element number %i : %s\n", $i+1,$elements[$i]; }  Python code # Loop foreach elements = ['a', 'b', 'c', 'd', 'e', 'f'] count = 0 for element in elements: count += 1 print("Element number {} : {}".format(count, element)) # Pythonic version elements = ['a', 'b', 'c', 'd', 'e', 'f'] for index, element in enumerate(elements): print("Element number {} : {}".format(index, element))  ## LISP only tricks ### Store/restore data on disk The simplest way to store data in LISP is to write a data structure into a file, using print function. The code output with print can be evaluated later with read. Common Lisp code (defun restore-data(file) (when (probe-file file) (with-open-file (x file :direction :input) (read x)))) (defun save-data(file data) (with-open-file (x file :direction :output :if-does-not-exist :create :if-exists :supersede) (print data x))) ;; using the functions (save-data "books.lisp" *books*) (defparameter *books* (restore-data "books.lisp"))  This permit to skip the use of a data storage format like XML or JSON. Common LISP can read Common LISP, this is all it needs. It can store objets like arrays, lists or structures using plain text format. It can’t dump hash tables directly. ### Creating a new syntax with a simple macro Sometimes we have cases where we need to repeat code and there is no way to reduce it because it’s too much specific or because it’s due to the language itself. Here is an example where we can use a simple macro to reduce the written code in a succession of conditions doing the same check. We will start from this Common Lisp code (when value (when (string= line-type "3") (progn (print-with-color "error" 'red line-number) (log-to-file "error"))) (when (string= line-type "4") (print-with-color text)) (when (string= line-type "5") (print-with-color "nothing")))  to this, using a macro Common Lisp code (defmacro check(identifier &body code) (progn (when (string= line-type ,identifier) ,@code))) (when value (check "3" (print-with-color "error" 'red line-number) (log-to-file "error")) (check "4" (print-with-color text)) (check "5" (print-with-color "nothing")))  The code is much more readable and the macro is easy to understand. One could argue that in another language a switch/case could work here, I choosed a simple example to illustrate the use of a macro, but they can achieve more. ### Create powerful wrappers with macros I’m using macros when I need to repeat code that affect variables. A lot of CL modules offers a structure like with-something, it’s a wrapper macro that will do some logic like opening a database, checking it’s opened, closing it at the end and executing your code inside. Here I will write a tiny http request wrapper, allowing me to write http request very easily, my code being able to use variables from the macro. Common Lisp code (defmacro with-http(url) (progn (multiple-value-bind (content status head) (drakma:http-request ,url :connection-timeout 3) (when content ,@code)))) (with-http "https://dataswamp.org/" (format t "We fetched headers ~a with status ~a. Content size is ~d bytes.~%" status head (length content)))  In Perl, the following would be written like this Perl code sub get_http { my$url = $1; my %http = magic_http_get$url;
if($http{content}) { return %http; } else { return undef; } } { local %data = get_http "https://dataswamp.org/"; if(%data) { printf "We fetched headers %s with status %d. Content size is %d bytes.\n",$http{headers}, $http{status}, length($http{content});
}
}


The curly brackets are important there, I want to emphase that the local %data variable is only available inside the curly brackets. Lisp is written in a successive of local scope and this is something I really like.

Python code

import requests
with requests.get("https://dataswamp.org/") as fd:
print("We fetched headers %s with status %d. Content size is %s bytes." \


# Allow wide resolution on intel graphics laptop

Written by Solène, on 22 November 2017.
Tags: #hardware

I just received a wide screen with a 2560x1080 resolution but xrandr wasn’t allowing me to use it. The intel graphics specifications say that I should be able to go up to 4096xsomething so it’s a software problem.

Generate the informations you need with gtf

$gtf 2560 1080 59.9  Takes only the numbers after the resolution name between quotes, so in Modeline "2560x1080_59.90" 230.37 2560 2728 3000 3440 1080 1081 1084 1118 -HSync +Vsync keep only 230.37 2560 2728 3000 3440 1080 1081 1084 1118 -HSync +Vsync Now add the new resolution and make it available to your output (mine is HDMI2): $ xrandr --newmode "2560x1080" 230.37 2560 2728 3000 3440 1080 1081 1084 1118 -HSync +Vsync
$xrandr --addmode HDMI2 2560x1080  You can now use this mode with arandr using the GUI or with xrandr by typing xrandr --output HDMI1 --mode 2560x1080 You will need to set the new mode each time the system start. I added the 2 lines in my ~/.xsession file which starts stumpwm. # Low bandwidth : Fetch OpenBSD sources Written by Solène, on 09 November 2017. Tags: #openbsd #bandwidth When you fetch OpenBSD src or ports from CVS and that you want to save bandwidth during the process there is a little trick that change everything: compression Just add -z9 to the parameter of your cvs command line and the remote server will send you compressed files, saving 10 times the bandwidth, or speeding up 10 times the transfer, or both (I’m in the case where I have differents users on my network and I’m limiting my incoming bandwidth so other people can have bandwidth too so it is important to reduce the packets transffered if possible). The command line should looks like: $ cvs -z9 -qd anoncvs@anoncvs.fr.openbsd.org:/cvs checkout -P src


# Gentoo port of the week : slrn

Written by Solène, on 08 November 2017.
Tags: #gentoo #portoftheweek #bandwidth

## Introduction

Hello,

Today I will speak about slrn, a nntp client. I’m using it to fetch mailing lists I’m following (without necesserarly subscribing to them) and read it offline. I’ll speak about using nntp to read news-groups, I’m not sure but in a more general way nntp is used to access usenet. I’m not sure to know what usenet is, so we will stick here by connecting to mailing-list archives offered by gmane.org (which offers access to mailing-lists and newsgroups through nntp).

Long story short, recently I moved and now I have a very poor DSL connection. Plus I’m often moving by train with nearly no 4G/LTE support during the trip. I’m going to write about getting things done offline and about reducing bandwith usage. This is a really interesting topic in our hyper-connected world.

So, back to slrn, I want to be able to fetch lot of news and read it later. Every nntp client I tried were getting the articles list (in nntp, an article = a mail, a forum = mailing list) and then it download each article when we want to read it. Some can cache the result when you fetch an article, so if you want to read it later it is already fetched. While slrn doesn’t support caching at all, it comes with the utility slrnpull which will create a local copy of forums you want, and slrn can be configured to fetch data from there. slrnpull need to be configured to tell it what to fetch, what to keep etc… and a cron will start it sometimes to fetch the new articles.

## Configuration

The following configuration is made to be simple to use, it runs with your regular user. This is for gentoo, maybe some another system would provide a dedicated user and everything pre-configured.

Create the folder for slrnpull and change the owner:

$sudo mkdir /var/spool/slrnpull$ sudo chown user /var/spool/slrnpull


slrnpull configuration file must be placed in the folder it will use. So edit /var/spool/slrnpull/slrnpull.conf as you want, my configuration file is following.

default 200 45 0
# indicates a default value of 20 articles to be retrieved from the server and
# that such an article will expire after 14 days.

gmane.network.gopher.general
gmane.os.freebsd.questions
gmane.os.freebsd.devel.ports
gmane.os.openbsd.misc
gmane.os.openbsd.ports
gmane.os.openbsd.bugs


The client slrn needs to be configured to find the informations from slrnpull.

File ~/.slrnrc:

set hostname "your.hostname.domain"
set spool_inn_root "/var/spool/slrnpull"
set spool_root "/var/spool/slrnpull/news"
set spool_nov_root "/var/spool/slrnpull/news"
set use_slrnpull 1
set post_object "slrnpull"
set server_object "spool"


Add this to your crontab to fetch news once per hour (at HH:00 minutes):

0 * * * * NNTPSERVER=news.gmane.org slrnpull -d /var/spool/slrnpull/


Now, just type slrn and enjoy.

## Cheat Sheet

Quick cheat sheet for using slrn, there is a help using “?” but it is not very easy to understand at first.

• h : hide/display the article view
• space : scroll to next page in the article, go to next at the end
• enter : scroll one line
• tab : scroll to the end of quotes
• c : mark all as read

## Tips

• when a forum is empty, it is not shown by default

I found that a slrnconf software provide a GUI to configure slrn exists, I didn’t try it.

## Going further

It seems nntp clients supports a score file that can mark interesting articles using user defined rules.

nntp protocol allow to submit articles (reply or new thread) but I have no idea how it works. Someone told me to forget about this and use mails to mailing-lists when it is possible.

leafnode daemon can be used instead of slrnpull in a more generic way. It is a nntp server that one would use locally as a proxy to nntp servers. It will mirror forums you want and serve it back through nntp, allowing you to use any nntp client (slrnpull enforces the use of slrn). leafnode seems old, a v2 is still in development but seems rather inactive. Leafnode is old and complicated, I wanted something KISS (Keep It Simple Stupid) and it is not.

## Others clients you may want to try

nntp console client

• gnus (in emacs)
• wanderlust (in emacs too)
• alpine

GUI client

• pan (may be able to download, but I failed using it)
• seamonkey (the whole mozilla suite supports nntp)

# Gopher related software

Written by Solène, on 25 October 2017.
Tags: #gopher

## Pages generator

• http://git.r–36.net/zs/

# Zooming with emacs, tmux or stumpwm

Written by Solène, on 25 October 2017.
Tags: #emacs #stumpwm #tmux

Hey ! You use stumpwm, emacs or tmux and your screen (not the GNU screen) split in lot of parts ? There is a solution to improve that. ZOOMING !

Each of them work with a screen divided into panes/windows (the meaning of theses words change between the program), sometime you want want to have the one where your work in fullscreen. An option exists in each of them to get fullscreen temporarly on a window.

## Emacs: (not native)

This is not native in emacs, you will need to install zoom-window from your favorite repository.

(require 'zoom-window)
(global-set-key (kbd "C-x C-z") 'zoom-window-zoom)


Type C-x C-z to zoom/unzoom your current frame

## Tmux

Toogle zoom (in or out)

C-b z


## Stumpwm

(define-key *root-map* (kbd "z")            "fullscreen")


Using “prefix z” the current window will toggle fullscreen.

# Gentoo port of the week : Nethogs

Written by Solène, on 17 October 2017.
Tags: #gentoo #portoftheweek

Today I will present you a nice port (from Gentoo this time, not from a FreeBSD) and this port is even linux only.

nethogs is a console program which shows the bandwidth usage of each running application consuming network. This can be particulary helpful to find which application is sending traffic and at which rate.

It can be installed with emerge as simple as emerge -av net-analyzer/nethogs.

It is very simple of use, just type nethogs in a terminal (as root). There are some parameters and it’s a bit interactive but I recommend reading the manual if you need some details about them.

I am currently running Gentoo on my main workstation, that makes me discover new things so maybe I will write more regularly about gentoo ports.

# How to limit bandwidth usage of emerge in Gentoo

Written by Solène, on 16 October 2017.
Tags: #gentoo

If for some reason you need to reduce the download speed of emerge when downloading sources you can use a tweak in portage’s make.conf as explained in the handbook.

To keep wget and just add the bandwidth limit, add this to /etc/portage/make.conf:

FETCHCOMMAND="${FETCHCOMMAND} --limit-rate=200k"  Of course, adjust your rate to your need. # Display manually installed packages on FreeBSD Written by Solène, on 16 August 2017. Tags: #freebsd If you want to show the packages installed manually (and not installed as dependency of another package), you have to use “pkg query” and compare if %a (automatically installed == 1) isn’t 1. The second string will format the output to display the package name: $ pkg query -e "%a != 1" "%n"


# Using firefox on Guix distribution

Written by Solène, on 16 August 2017.
Tags: #guix

I’m new to Guix, it’s a wonderful system but it’s such different than any other usual linux distribution that it’s hard to achieve some basics tasks. As Guix is 100% free/libre software, Firefox has been removed and replaced by icecat. This is nearly the same software but some “features” has been removed (like webRTC) for some reasons (security, freedom). I don’t blame Guix team for that, I understand the choice.

But my problem is that I need Firefox. I finally achieve to get it working from the official binary downloaded from mozilla website.

You need to install some packages to get the libraries, which will become available under your profile directory. Then, tells firefox to load libraries from there and it will start.

guix package -i glibc glib gcc gtk+ libxcomposite dbus-glib libxt
LD_LIBRARY_PATH=~/.guix-profile/lib/ ~/.guix-profile/lib/ld-linux-x86-64.so.2 ~/firefox_directory/firefox


Also, it seems that running icecat and firefox simultanously works, they store data in ~/.mozilla/icecat and ~/.mzoilla/firefox so they are separated.

# Using emacs to manage mails with mu4e

Written by Solène, on 15 June 2017.
Tags: #emacs #mail

In this article we will see how to fetch, read and manage your emails from Emacs using mu4e. The process is the following: mbsync command (while mbsync is the command name, the software name is isync) create a mirror of an imap account into a Maildir format on your filesystem. mu from mu4e will create a database from the Maildir directory using xapian library (full text search database), then mu4e (mu for emacs) is the GUI which queries xapian database to manipulates your mails.

Mu4e handles with dynamic bookmarks, so you can have some predefined filters instead of having classic folders. You can also do a query and reduce the results with successives queries.

You may have heard about using notmuch with emacs to manage mails, mu4e and notmuch doesn’t do the same job. While notmuch is a nice tool to find messages from queries and create filters, it operates as a read-only tool and can’t do anything with your mail. mu4e let you write mail, move, delete, flag etc… AND still allow to make complex queries.

I wrote this article to allow people to try mu4e quickly, you may want to read both isync and mu4e manual to have a better configuration suiting your needs.

## Installation

On OpenBSD you need to install 2 packages:

# pkg_add mu4e isync


## isync configuration

We need to configure isync to connect to the IMAP server:

Edit the file ~/.mbsyncrc, there is a trick to not have the password in clear text in the configuration file, see isync configuration manual for this:

iMAPAccount my_imap
Host my_host_domain.info
User imap_user
Pass my_pass_in_clear_text
SSLType IMAPS

IMAPStore my_imap-remote
Account my_imap

MailDirStore my_imap-local
Path ~/Maildir/my_imap/
Inbox ~/Maildir/my_imap/Inbox
SubFolders Legacy

channel my_imap
Master :my_imap-remote:
Slave :my_imap-local:
Patterns *
Create Slave
Expunge Both


## mu4e / emacs configuration

We need to configure mu4e in order to tell where to find the mail folder. Add this to your ~/.emacs file.

(require 'mu4e)
(setq mu4e-maildir "~/Maildir/my_imap/"
mu4e-sent-folder "/Sent Messages/"
mu4e-trash-folder "/Trash"
mu4e-drafts-folder "/Drafts")


## First start

A few commands are needed in order to make everything works. We need to create the base folder as mbsync command won’t do the job for some reason, and we need mu to index the mails the first time.

$mkdir -p ~/Maildir/my_imap$ mbsync -aC
$mu index --maildir=~/Maildir/my_imap  ## How to use mu4e start emacs, run M-x mu4e RET and enjoy, the documentation of mu4e is well done. Press “U” at mu4e screen to synchronize with imap server. A query for mu4e looks like this: list:misc.openbsd.org flag:unread avahi  This query will search mails having list header “misc.openbsd.org” and which are unread and which contains “avahi” pattern. date:20140101..20150215 urgent  This one will looks for mails within date range of 1st january 2014 to 15th february 2015 containing word “urgent”. ## Additional notes The current setup doesn’t handle sending mails, I’ll write another article about this. This requires configuring a smtp authentification and an identify for mu4e. Also, you may need to tweak mbsync configuration or mu4e configuration, some settings must be changed depending on the imap server, this is particuliarly important for deleted mails. # Fold functions in emacs Written by Solène, on 16 May 2017. Tags: #emacs You want to fold (hide) code between brackets like an if statement, a function, a loop etc.. ? Use the HideShow minor-mode which is part of emacs. All you need is to enable hs-minor-mode. Now you can fold/unfold by cycling with C-c @ C-c. HideShow on EmacsWiki # How to change Firefox locale to ... esperanto? Written by Solène, on 14 May 2017. Tags: #firefox Hello ! Today I felt the need to change the language of my Firefox browser to esperanto but I haven’t been able to do this, it is not straightforward… First, you need to install your language pack, depending if you use the official Mozilla Firefox or Icecat, the rebranded firefox with non-free stuff removed Then, open about:config in firefox, we will need to change 2 keys. Firefox needs to know that we don’t want to use our user’s locale as Firefox language and which language we want to set. • set intl.locale.matchOS to false • set general.useragent.locale to the language code you want (eo for esperanto) • restart firefox/icecat you’re done ! Bonan tagon # Bandwidth limit / queue on OpenBSD 6.1 Written by Solène, on 25 April 2017. Tags: #openbsd #unix #network Today I will explain how to do traffic limit with OpenBSD and PF. This is not hard at all if you want something easy, the man page pf.conf(5) in QUEUEING section is pretty good but it may disturbing when you don’t understand how it works. This is not something I master, I’m not sure of the behaviour in some cases but the following example works as I tested it ! :) ### Use case Internet is down at home, I want to use my phone as 4G router trough my OpenBSD laptop which will act as router. I don’t want the quota (some Gb) to be eaten in a few seconds, this connection allow to download up to 10 Mb/s so it can go quickly ! We will limit the total bandwidth to 1M (~ 110 kb/s) for people behind the NAT. It will be slow, but we will be sure that nothing behind the NAT like a program updating, cloud stuff synchronizing or videos in auto play won’t consume our quota. Edit /etc/pf.conf accordigly to your network internet="urndis0" lan="em0" # we define our available bandwidth queue main on$lan bandwidth 100M

# we will let 1M but we will allow
# 3M during 200 ms when initiating connection to keep the web a bit interactive
queue limited parent main bandwidth 1M min 0K max 1M burst 3M for 200ms default

set skip on lo

# we do NAT here
match out on egress inet from !(egress:network) to any nat-to (egress:0)

block all
pass out quick inet

# we apply the queue here on EVERYTHING coming from the internet
pass in on $lan proto tcp port www set queue web  ### Per host ? As before, you can apply queues on IP host/range rather than protocols, or you can even mix both if you want. ### Warning The limit function changed in OpenBSD 5.5, everything you can read on the internet about ALTQ isn’t working anymore. # Markup languages comparison Written by Solène, on 13 April 2017. Tags: #unix For the fun, here is a few examples of the same output in differents markup languages. The list isn’t exhaustive of course. This is org-mode: * This is a title level 1 + first item + second item + third item with a [[http://dataswamp.org][link]] ** title level 2 Blah blah blah blah blah blah blah blah *bold* here #+BEGIN_SRC lisp (let ((hello (init-string))) (format t "~A~%" (+ 1 hello)) (print hello)) #+END_SRC  This is markdown : # this is title level 1 + first item + second item + third item with a [Link](http://dataswamp.org) ## Title level 2 Blah blah blah blah blah blah blah blah **bold** here (let ((hello (init-string))) (format t "~A~%" (+ 1 hello)) (print hello)) or  (let ((hello (init-string))) (format t "~A~%" (+ 1 hello)) (print hello))   This is HTML : <h1>This is title level 1</h1> <ul> <li>first item></li> <li>second item</li> <li>third item with a <a href="http://dataswamp.org">link</a></li> </ul> <h2>Title level 2</h2> <p>Blah blah blah blah blah blah blah blah <strong>bold</strong> here <code><pre>(let ((hello (init-string))) (format t "~A~%" (+ 1 hello)) (print hello))</pre></code>  This is LaTeX : \begin{document} \section{This is title level 1} \begin{itemize} \item First item \item Second item \item Third item \end{itemize} \subsection{Title level 2} Blah blah blah blah blah blah blah blah \textbf{bold} here \begin{verbatim} (let ((hello (init-string))) (format t "~A~%" (+ 1 hello)) (print hello)) \end{verbatim} \end{document}  # OpenBSD 6.1 released Written by Solène, on 11 April 2017. Tags: #openbsd #unix Today OpenBSD 6.1 has been released, I won’t copy & paste the change list but, in a few words, it gets better. Link to the official announce I already upgraded a few servers, with both methods. One with bsd.rd upgrade but that requires physical access to the server and the other method well explained in the upgrade guide which requires to untar the files and do move some files. I recommend using bsd.rd if possible. # Connect to pfsense box console by usb Written by Solène, on 10 April 2017. Tags: #unix #network #openbsd Hello, I have a pfsense appliance (Netgate 2440) with a usb console port, while it used to be a serial port, now devices seems to have a usb one. If you plug an usb wire from an openbsd box to it, you woull see this in your dmesg uslcom0 at uhub0 port 5 configuration 1 interface 0 "Silicon Labs CP2104 USB to UART Bridge Controller" rev 2.00/1.00 addr 7 ucom0 at uslcom0 portno 0  To connect to it from OpenBSD, use the following command: # cu -l /dev/cuaU0 -s 115200  And you’re done # List of useful tools Written by Solène, on 22 March 2017. Tags: #unix Here is a list of software that I find useful, I will update this list everytime I find a new tool. This is not an exhaustive list, theses are only software I enjoy using: ## Backup Tool • duplicity • borg • restore/dump ## File synchronization tool • unison • rsync • lsyncd ## File sharing tool / “Cloud” • boar • nextcloud / owncloud • seafile • pydio • syncthing (works as peer-to-peer without a master) • sparkleshare (uses a git repository so I would recommend storing only text files) ## Editors • emacs • vim • jed ## Web browsers using keyboard • qutebrowser • firefox with vimperator extension ## Todo list / Personal Agenda… • org-mode (within emacs) • ledger (accounting) ## Mail client • mu4e (inside emacs, requires the use of offlineimap or mbsync to fetch mails) ## Network • curl • bwm-ng (to see bandwith usage in real time) • mtr (traceroute with a gui that updates every n seconds) ## Files integrity • bitrot • par2cmdline • aide ## Image viewer • sxiv • feh ## Stuff • entr (run command when a file change) • rdesktop (RDP client to connect to Windows VM) • xclip (read/set your X clipboard from a script) • autossh (to create tunnels that stays up) • mosh (connects to your ssh server with local input and better resilience) • ncdu (watch file system usage interactively in cmdline) • mupdf (PDF viewer) • pdftk (PDF manipulation tool) • x2x (share your mouse/keyboard between multiple computers through ssh) • profanity (XMPP cmdline client) • prosody (XMPP server) • pgmodeler (PostgreSQL database visualization tool) # How to check your data integrity? Written by Solène, on 17 March 2017. Tags: #unix #security #data Today, the topic is data degradation, bit rot, birotting, damaged files or whatever you call it. It’s when your data get corrupted over the time, due to disk fault or some unknown reason. # What is data degradation ? I shamelessy paste one line from wikipedia: “Data degradation is the gradual corruption of computer data due to an accumulation of non-critical failures in a data storage device. The phenomenon is also known as data decay or data rot.”. Data degradation on Wikipedia So, how do we know we encounter a bit rot ? bit rot = (checksum changed) && NOT (modification time changed)  While updating a file could be mistaken as bit rot, there is a difference update = (checksum changed) && (modification time changed)  # How to check if we encounter bitrot ? There is no way you can prevent bitrot. But there are some ways to detect it, so you can restore a corrupted file from a backup, or repair it with the right tool (you can’t repair a file with a hammer, except if it’s some kind of HammerFS ! :D ) In the following I will describe software I found to check (or even repair) bitrot. If you know others tools which are not in this list, I would be happy to hear about it, please mail me. In the following examples, I will use this method to generate bitrot on a file: % touch -d "2017-03-16T21:04:00" my_data/some_file_that_will_be_corrupted % generate_checksum_database_with_tool % echo "a" >> my_data/some_file_that_will_be_corrupted % touch -d "2017-03-16T21:04:00" my_data/some_file_that_will_be_corrupted % start_tool_for_checking  We generate the checksum database, then we alter a file by adding a “a” at the end of the file and we restore the modification and acess time of the file. Then, we start the tool to check for data corruption. The first touch is only for convenience, we could get the modification time with stat command and pass the same value to touch after modification of the file. ## bitrot This is a python script, it’s very easy to use. I will scan a directory and create a database with the checksum of the files and their modification date. Initialization usage: % cd /home/my_data/ % bitrot Finished. 199.41 MiB of data read. 0 errors found. 189 entries in the database, 189 new, 0 updated, 0 renamed, 0 missing. Updating bitrot.sha512... done. % echo$?
0


Verify usage (case OK):

% cd /home/my_data/
% bitrot
Checking bitrot.db integrity... ok.
Finished. 199.41 MiB of data read. 0 errors found.
189 entries in the database, 0 new, 0 updated, 0 renamed, 0 missing.
% echo $? 0  Exit status is 0, so our data are not damaged. Verify usage (case Error): % cd /home/my_data/ % bitrot Checking bitrot.db integrity... ok. error: SHA1 mismatch for ./sometextfile.txt: expected 17b4d7bf382057dc3344ea230a595064b579396f, got db4a8d7e27bb9ad02982c0686cab327b146ba80d. Last good hash checked on 2017-03-16 21:04:39. Finished. 199.41 MiB of data read. 1 errors found. 189 entries in the database, 0 new, 0 updated, 0 renamed, 0 missing. error: There were 1 errors found. % echo$?
1


When something is wrong. As the exit status of bitrot isn’t 0 when it fails, it’s easy to write a script running every day/week/month.

Github page

bitrot is available in OpenBSD ports in sysutils/bitrot since 6.1 release.

## par2cmdline

This tool works with PAR2 archives (see below for more informations about what PAR ) and from them, it will be able to check your data integrity AND repair it.

While it has some pros like being able to repair data, the cons is that it’s not very easy to use. I would use this one for checking integrity of long term archives that won’t changes. The main drawback comes from PAR specifications, the archives are created from a filelist, if you have a directory with your files and you add new files, you will need to recompute ALL the PAR archives because the filelist changed, or create new PAR archives only for the new files, but that will make the verify process more complicated. That doesn’t seems suitable to create new archives for every bunchs of files added in the directory.

PAR2 let you choose the percent of a file you will be able to repair, by default it will create the archives to be able to repair up to 5% of each file. That means you don’t need a whole backup for the files (while it’s would be a bad idea) and only an approximately extra of 5% of your data to store.

Create usage:

% cd /home/
% par2 create -a integrity_archive -R my_data
Skipping 0 byte file: /home/my_data/empty_file

Block size: 3812
Source file count: 17
Source block count: 2000
Redundancy: 5%
Recovery block count: 100
Recovery file count: 7

Opening: my_data/[....]
[text cut here]
Opening: my_data/[....]

Computing Reed Solomon matrix.
Constructing: done.
Wrote 381200 bytes to disk
Writing recovery packets
Writing verification packets
Done

% echo $? 0 % ls -1 integrity_archive.par2 integrity_archive.vol000+01.par2 integrity_archive.vol001+02.par2 integrity_archive.vol003+04.par2 integrity_archive.vol007+08.par2 integrity_archive.vol015+16.par2 integrity_archive.vol031+32.par2 integrity_archive.vol063+37.par2 my_data  Verify usage (OK): % par2 verify integrity_archive.par2 Loading "integrity_archive.par2". Loaded 36 new packets Loading "integrity_archive.vol000+01.par2". Loaded 1 new packets including 1 recovery blocks Loading "integrity_archive.vol001+02.par2". Loaded 2 new packets including 2 recovery blocks Loading "integrity_archive.vol003+04.par2". Loaded 4 new packets including 4 recovery blocks Loading "integrity_archive.vol007+08.par2". Loaded 8 new packets including 8 recovery blocks Loading "integrity_archive.vol015+16.par2". Loaded 16 new packets including 16 recovery blocks Loading "integrity_archive.vol031+32.par2". Loaded 32 new packets including 32 recovery blocks Loading "integrity_archive.vol063+37.par2". Loaded 37 new packets including 37 recovery blocks Loading "integrity_archive.par2". No new packets found There are 17 recoverable files and 0 other files. The block size used was 3812 bytes. There are a total of 2000 data blocks. The total size of the data files is 7595275 bytes. Verifying source files: Target: "my_data/....." - found. [...cut here...] Target: "my_data/....." - found. All files are correct, repair is not required. % echo$?
0


Verify usage (with error):

par2 verify integrity_archive.par.par2
Loaded 1 new packets including 1 recovery blocks
Loaded 2 new packets including 2 recovery blocks
Loaded 4 new packets including 4 recovery blocks
Loaded 8 new packets including 8 recovery blocks
Loaded 16 new packets including 16 recovery blocks
Loaded 32 new packets including 32 recovery blocks
Loaded 37 new packets including 37 recovery blocks
No new packets found

There are 17 recoverable files and 0 other files.
The block size used was 3812 bytes.
There are a total of 2000 data blocks.
The total size of the data files is 7595275 bytes.

Verifying source files:

Target: "my_data/....." - found.
[...cut here...]
Target: "my_data/....." - found.
Target: "my_data/Ebooks/Lovecraft/Quete Onirique de Kadath l'Inconnue.epub" - damaged. Found 95 of 95 data blocks.

Scanning extra files:

Repair is required.
1 file(s) exist but are damaged.
16 file(s) are ok.
You have 2000 out of 2000 data blocks available.
You have 100 recovery blocks available.
Repair is possible.
You have an excess of 100 recovery blocks.
None of the recovery blocks will be used for the repair.

% echo $? 1  Repair usage: % par2 repair integrity_archive.par.par2 Loading "integrity_archive.par.par2". Loaded 36 new packets Loading "integrity_archive.par.vol000+01.par2". Loaded 1 new packets including 1 recovery blocks Loading "integrity_archive.par.vol001+02.par2". Loaded 2 new packets including 2 recovery blocks Loading "integrity_archive.par.vol003+04.par2". Loaded 4 new packets including 4 recovery blocks Loading "integrity_archive.par.vol007+08.par2". Loaded 8 new packets including 8 recovery blocks Loading "integrity_archive.par.vol015+16.par2". Loaded 16 new packets including 16 recovery blocks Loading "integrity_archive.par.vol031+32.par2". Loaded 32 new packets including 32 recovery blocks Loading "integrity_archive.par.vol063+37.par2". Loaded 37 new packets including 37 recovery blocks Loading "integrity_archive.par.par2". No new packets found There are 17 recoverable files and 0 other files. The block size used was 3812 bytes. There are a total of 2000 data blocks. The total size of the data files is 7595275 bytes. Verifying source files: Target: "my_data/....." - found. [...cut here...] Target: "my_data/....." - found. Target: "my_data/Ebooks/Lovecraft/Quete Onirique de Kadath l'Inconnue.epub" - damaged. Found 95 of 95 data blocks. Scanning extra files: Repair is required. 1 file(s) exist but are damaged. 16 file(s) are ok. You have 2000 out of 2000 data blocks available. You have 100 recovery blocks available. Repair is possible. You have an excess of 100 recovery blocks. None of the recovery blocks will be used for the repair. Wrote 361069 bytes to disk Verifying repaired files: Target: "my_data/Ebooks/Lovecraft/Quete Onirique de Kadath l'Inconnue.epub" - found. Repair complete. % echo$?
0


par2cmdline is only one implementation doing the job, others tools working with PAR archives exists. They should be able to all works with the same PAR files.

Parchive on Wikipedia

Github page

par2cmdline is available in OpenBSD ports in archivers/par2cmdline.

If you find a way to add new files to existing archives, please mail me.

## mtree

One can write a little script using mtree (in base system on OpenBSD and FreeBSD) which will create a file with the checksum of every files in the specified directories. If mtree output is different since last time, we can send a mail with the difference. This is a process done in base install of OpenBSD for /etc and some others files to warn you if it changed.

While it’s suited for directories like /etc, in my opinion, this is not the best tool for doing integrity check.

## ZFS

I would like to talk about ZFS and data integrity because this is where ZFS is very good. If you are using ZFS, you may not need any other software to take care about your data. When you write a file, ZFS will also store its checksum as metadata. By default, the option “checksum” is activated on dataset, but you may want to disable it for better performance.

There is a command to ask ZFS to check the integrity of the files. Warning: scrub is very I/O intensive and can takes from hours to days or even weeks to complete depending on your CPU, disks and the amount of data to scrub:

# zpool scrub zpool


The scrub command will recompute the checksum of every file on the ZFS pool, if something is wrong, it will try to repair it if possible. A repair is possible in the following cases:

If you have multiple disks like raid-Z or raid–1 (mirror), ZFS will be look on the differents disks if the non corrupted version of the file exists, if it finds it, it will restore it on the disk(s) where it’s corrupted.

If you have set the ZFS option “copies” to 2 or 3 (1 = default), that means that the file is written 2 or 3 time on the disk. Each file of the dataset will be allocated 2 or 3 time on the disk, so take care if you want to use it on a dataset containing heavy files ! If ZFS find thats a version of a file is corrupted, it will check the others copies of it and tries to restore the corrupted file is possible.

You can see the percentage of filesystem already scrubbed with

zfs status zpool


and the scrub can be stopped with

zfs scrub -s zpool


### AIDE

Its name is an acronym for “Advanced Intrusion Detection Environment”, it’s an complicated software which can be used to check for bitrot. I would not recommend using it if you only need bitrot detection.

Here is a few hints if you want to use it for checking your file integrity:

/etc/aide.conf

/home/my_data/ R
# Rule definition
All=m+s+i+sha256
summarize_changes=yes


The config file will create a database of all files in /home/my_data/ (R for recursive). “All” line list the checks we do on each file. For bitrot checking, we want to check modification time, size, checksum and inode of the files. The summarize_change line permit to have a list of changes if something is wrong.

This is the most basic config file you can have. Then you will have to run aide to create the database and then run aide to create a new database and compare the two databases. It doesn’t update its database itself, you will have to move the old database and tell it where to found the older database.

# My use case

I have different kind of data. On a side, I have static data like pictures, clips, music or things that won’t change over time and the other side I have my mails, documents and folders where the content changes regularly (creation, deletetion, modification). I am able to afford a backup for 100% of my data with some history of the backup on a few days, so I won’t be interested about file repairing.

I want to be warned quickly if a file get corrupted, so I can still get the backup in my history but I don’t keep every versions of my files for too long. I choose to go with the python tool bitrot, it’s very easy to use and it doesn’t become a mess with my folders getting updated often.

I would go with par2cmdline if I could not be able to backup all my data. Having 5% or 10% of redundancy of my files should be enough to restore it in case of corruption without taking too much space.

# Port of the week : rss2email

Written by Solène, on 24 January 2017.
Tags: #portoftheweek #unix

This is the kind of Port of the week I like. This is a software I just discovered and fall in love to. The tool r2e which is the port mail/rss2email on OpenBSD is a small python utility that solves a problem: how to deal with RSS feeds?

Until last week, I was using a “web app” named selfoss which was aggregating my RSS feeds and displaying it on a web page, I was able to filter by read/unread/marked and also filter by source. It is a good tool that does the job well but I wanted something that doesn’t rely on a web browser. Here comes r2e !

This simple software will send you a mail for each new entry in your RSS feeds. It’s really easy to configure and set-up. Just look at how I configured mine:

$r2e new my-address+rss@my-domain.com$ r2e add "http://undeadly.org/cgi?action=rss"
$r2e add "https://dataswamp.org/~solene/rss.xml"$ r2e add "https://www.dragonflydigest.com/feed"
$r2e add "http://phoronix.com/rss.php"  Add this in your crontab to check new RSS items every 10 minutes: */10 * * * * /usr/local/bin/r2e run  Add a rule for my-address+rss to store mails in a separate folder, and you’re done ! NOTE: you can use r2e run –no-send for the first time, it will create the database and won’t send you mails for current items in feeds. # Dovecot : folder appears empty Written by Solène, on 23 January 2017. Tags: #dovecot #solved Today I encountered an unknown issue to me with my Imap server dovecot. In roundcube mail web client, my Inbox folder appeared empty after being reading a mail. My Android mail client K9-Mail was displaying “IOException:readStringUnti….” when trying to synchronize this folder. I solved it easily by connecting to my server with SSH, cd-ing into the maildir directory and in the Inbox folder, renamed dovecot.index.log to dovecot.index.log.bak (you can remove it if it fix the problem). And now, mails are back. This is the very first time I have a problem of this kind with dovecot… # New cl-yag version Written by Solène, on 21 January 2017. Tags: #lisp #cl-yag Today I just updated my tool cl-yag that implies a slightly change on my website. Now, on the top of this blog, you can see a link “Index of articles”. This page only display articles titles, without any text from the article. Cl-yag is a tool to generate static website like this one. It’s written in Common LISP. For reminder, it’s also capable of producing both html and gopher output now. If you don’t know what Gopher is, you will learn a lot reading the following links Wikipedia : Gopher (Protocol) and Why is gopher still relevant # Let's encrypt on OpenBSD in 5 minutes Written by Solène, on 20 January 2017. Tags: #letsencrypt #openbsd Let’s encrypt is a free service which provides free SSL certificates. It is fully automated and there are a few tools to generate your certificates with it. In the following lines, I will just explain how to get a certificate in a few minutes. You can find more informations on Let’s Encrypt website. To make it simple, the tool we will use will generate some keys on the computer, send a request to Let’s Encrypt service which will use http challenging (there are also dns and another one kind of challenging) to see if you really own the domain for which you want the certificate. If the challenge process is ok, you have the certificate. Please, if you don’t understand the following commands, don’t type it. While the following is right for OpenBSD, it may change slightly for others systems. Acme-client is part of the base system, you can read the man page acme-client(1). ## Prepare your http server For each certificate you will ask a certificate, you will be challenged for each domain on the port 80. A file must be available in a path under “/.well-known/acme-challenge/”. You must have this in your httpd config file. If you use another web server, you need to adapt. server "mydomain.com" { root "/empty" listen on * port 80 location "/.well-known/acme-challenge/*" { root { "/acme/" , strip 2 } } }  The “strip 2” part is IMPORTANT. (I’ve lost 45 minutes figuring out why root “/acme/” wasn’t working.) ## Prepare the folders As stated in acme-client man page and if you don’t need to change the path. You can do the following commands with root privileges : # mkdir /var/www/acme # mkdir -p /etc/ssl/acme/private /etc/acme # chmod 0700 /etc/ssl/acme/private /etc/acme  ## Request the certificates As root, in the acme-client sources folder, type the following the generate the certificates. The verbose flag is interesting and you will see if the challenging step work. If it doesn’t work, you should try manually to get a file like with the same path tried from Let’s encrypt, and try again the command when you succeed. $ acme-client -vNn mydomain.com www.mydomain.com mail.mydomain.com


## Use the certificates

Now, you can use your SSL certificates for your mail server, imap server, ftp server, http server…. There is a little drawback, if you generate certificates for a lot of domains, they are all written in the certificate. This implies that if someone visit one page, look at the certificate, this person will know every domain you have under SSL. I think that it’s possible to ask every certificate independently but you will have to play with acme-client flags and make some kind of scripts to automatize this.

Certificate file is located at /etc/ssl/acme/fullchain.pem and contains the full certification chain (as its name is explicit). And the private key is located at /etc/ssl/acme/private/privkey.pem.

Restart the service with the certificate.

## Renew certificates

Certificates are valid for 3 months. Just type

./acme-client mydomain.com www.mydomain.com mail.mydomain.com


EASY !

# How to use ssh tramp on Emacs Windows?

Written by Solène, on 18 January 2017.
Tags: #emacs #windows

If you are using emacs under Microsoft Windows and you want to edit remote files through SSH, it’s possible to do it without using Cygwin. Tramp can use the tool “plink” from putty tools to do ssh.

What you need is to get “plink.exe” from the following page and get it into your $PATH, or choose the installer which will install all putty tools. Putty official website Then, edit your emacs file to add the following lines to tell it that you want to use plink when using tramp (require 'tramp) (set-default 'tramp-default-method "plink")  Now, you can edit your remote files, but you will need to type your password. I think that in order to get password-less with ssh keys, you would need to use putty key agent. # Convert mailbox to maildir with dovecot Written by Solène, on 17 January 2017. Tags: #unix I have been using mbox format for a few years on my personal mail server. For those who don’t know what mbox is, it consists of only one file per folder you have on your mail client, each file containing all the mails of the corresponding folder. It’s extremely ineficient when you backup the mail directory because it must copy everything each time. Also, it reduces the system cache possibility of the server because if you have folders with lots of mails with attachments, it may not be cached. Instead, I switched to maildir, which is a format where every mail is a regular file on the file system. This takes a lot of inodes but at least, it’s easier to backup or to deal with it for analysis. Here how to switch from mbox to maildir with a dovecot tool. # dsync -u solene mirror mbox:~/mail/:INBOX=~/mail/inbox  That’s all ! In this case, my mbox folder was ~/mail/ and my INBOX file was ~/mail/inbox. It tooks me some time to find where my INBOX really was, at first I tried a few thing that didn’t work and tried a perl convert tool named mb2md.pl which has been able to extract some stuff but a lot of mails were broken. So I have been going back getting dsync working. If you want to migrate, the whole process looks like: # service smtpd stop modify dovecot/conf.d/10-mail.conf, replace the first line mail_location = mbox:~/mail:INBOX=/var/mail/%u # BEFORE mail_location = maildir:~/maildir # AFTER # service dovecot restart # dsync -u solene mirror mbox:~/mail/:INBOX=~/mail/inbox # service smtpd start  # Port of the week : entr Written by Solène, on 07 January 2017. Tags: #unix entr is a command line tool that let you run arbitrary command on file change. This is useful when you are doing something that requires some processing when you modify it. Recently, I have used it to edit a man page. At first, I had to run mandoc each time I modified to file to check the render. This was the first time I edited a man page so I had to modify it a lot to get what I wanted. I remembered about entr and this is how you use it: ls stagit.1 | entr mandoc /_  This simple command will run “mandoc stagit.1” each time stagit.1 is modified. The file names must be given by stdin to entr, and then use the characters sequence /_ to replace the names (like {} in find). The man page of entr is very well documented if you need more examples. # Emacs 25 : save cursor position Written by Solène, on 08 December 2016. Tags: #emacs Since I upgraded to Emacs 25 it was no longer saving my last cursor position in edited file. This is a feature I really like because I often fire and close emacs rather than keeping it opened. Before (< emacs 25) (setq save-place-file "~/.emacs.d/saveplace") (setq-default save-place t) (require 'saveplace)  Emacs 25 (save-place-mode t) (setq save-place-file "~/.emacs.d/saveplace") (setq-default save-place t)  That’s all :) # Port of the week : dnscrypt-proxy Written by Solène, on 19 October 2016. Tags: #unix #security #portoftheweek #dns Today I will talk about net/dnscrypt-proxy. This let you encrypt your DNS traffic between your resolver and the remote DNS recursive server. More and more countries and internet provider use DNS to block some websites, and now they tend to do “man in the middle” with DNS answers, so you can’t just use a remote DNS you find on the internet. While a remote dnscrypt DNS server can still be affected by such “man in the middle” hijack, there is a very little chance DNS traffic is altered in datacenters / dedicated server hosting. The article also deal with unbound as a dns cache because dnscrypt is a bit slow and asking multiple time the same domain in a few minutes is a waste of cpu/network/time for everyone. So I recommend setting up a DNS cache on your side (which can also permit to use it on a LAN). At the time I write this article, their is a very good explanation about “how to install it” is named dnscrypt-proxy–1.9.5p3 in the folder /usr/local/share/doc/pkg-readmes/. The following article is made from this file. (Article updated at the time of OpenBSD 6.3) While I write for OpenBSD this can be easily adapted to anthing else Unix-like. ### Install dnscrypt # pkg_add dnscrypt-proxy  ### Resolv.conf Modify your resolv.conf file to this /etc/resolv.conf : nameserver 127.0.0.1 lookup file bind options edns0  ### When using dhcp client If you use dhcp to get an address, you can use the following line to force having 127.0.0.1 as nameserver by modifying dhclient config file. Beware, if you use it, when upgrading the system from bsd.rd, you will get 127.0.0.1 as your DNS server but no service running. /etc/dhclient.conf : supersede domain-name-servers 127.0.0.1;  ### Unbound Now, we need to modify unbound config to tell him to ask DNS at 127.0.0.1 port 40. Please adapt your config, I will just add what is mandatory. Unbound configuration file isn’t in /etc because it’s chrooted /var/unbound/etc/unbound.conf: server: # this line is MANDATORY do-not-query-localhost: no forward-zone: name: "." forward-addr: 127.0.0.1@40 # address dnscrypt listen on  If you want to allow other to resolv through your unbound daemon, please see parameters interface and access-control. You will need to tell unbound to bind on external interfaces and allow requests on it. ### Dnscrypt-proxy Now we need to configure dnscrypt, pick a server in the following LIST /usr/local/share/dnscrypt-proxy/dnscrypt-resolvers.csv, the name is the first column. As root type the following (or use doas/sudo), in the example we choose dnscrypt.eu-nl as a DNS provider # rcctl enable dnscrypt_proxy # rcctl set dnscrypt_proxy flags -E -m1 -R dnscrypt.eu-nl -a 127.0.0.1:40 # rcctl start dnscrypt_proxy  ### Conclusion You should be able to resolv address through dnscrypt now. You can use tcpdump on your external interface to see if you see something on udp port 53, you should not see traffic there. If you want to use dig hostname -p 40 @127.0.0.1 to make DNS request to dnscrypt without unbound, you will need net/isc-bind which will provide /usr/local/bin/dig. OpenBSD base dig can’t use a port different than 53. # How to publish a git repository on http Written by Solène, on 07 October 2016. Tags: #unix #git Here is an how-to in order to make a git repository available for cloning through a simple http server. This method only allow people to fetch the repository, not to push. I wanted to set-up this to get my code, I don’t plan to have any commit on it from other people at this time so it’s enough. In a folder publicly available from your http server clone your repository in bare mode. As explained in the [https://git-scm.com/book/tr/v2/Git-on-the-Server-The-Protocols](man page): $ cd /var/www/htdocs/some-path/
$git clone --bare /path/to/git_project gitproject.git$ cd gitproject.git
$git update-server-info$ mv hooks/post-update.sample hooks/post-update
$chmod o+x hooks/post-update  Then you will be able to clone the repository with $ git clone https://your-hostname/some-path/gitproject.git


I’ve lost time because I did not execute git update-server-info so the clone wasn’t possible.

# Port of the week : rlwrap

Written by Solène, on 04 October 2016.
Tags: #unix #shell #portoftheweek

Today I will present misc/rlwrap which is an utility tool when you use some command-line software which doesn’t provide you a nice readline input. By using rlwrap, you will be able to use telnet, a language REPL or any command-line tool where you input text with an history of what you type, ability to use emacs bindings like C-a C-e M-Ret etc… I use it often with telnet or sbcl.

Usage :

$rlwrap telnet host port  # OpenBSD performance tuning for desktop Written by Solène, on 28 September 2016. Tags: #openbsd I am using the following lines in my /etc/sysctl.conf file, this boosted the performance on my multiples OpenBSD desktop: kern.maxvnodes=768000 kern.maxfiles=32768 kern.maxclusters=256000 kern.seminfo.semmni=1024 kern.seminfo.semmns=4096 kern.shminfo.shmmax=805306368 kern.bufcachepercent=90  # Common LISP : How to open an SSL / TLS stream Written by Solène, on 26 September 2016. Tags: #lisp #network Here is a tiny code to get a connection to an SSL/TLS server. I am writing an IRC client and an IRC bot too and it’s better to connect through a secure channel. This requires usocket and cl+ssl: (usocket:with-client-socket (socket stream *server* *port*) (let ((ssl-stream (cl+ssl:make-ssl-client-stream stream :external-format '(:iso-8859-1 :eol-style :lf) :unwrap-stream-p t :hostname *server*))) (format ssl-stream "hello there !~%") (force-output ssl-stream)))  # Port of the week : stumpwm Written by Solène, on 21 September 2016. Tags: #stumpwm #portoftheweek #wm #lisp When I started port of the week articles I was planning to write an article every week but now I don’t have much ports too speak about. Today is about x11/stumpwm ! I wrote about this window manager earlier. It’s now available in OpenBSD since 6.1 release. # Redirect stdin into a variable in shell Written by Solène, on 12 September 2016. Tags: #shell #unix If you want to write a script reading stdin and put it into a variable, there is an very easy way to procede : #!/bin/sh var=cat echo$var


That’s all

# Android phone and Unix

Written by Solène, on 06 September 2016.
Tags: #android #emacs

If you have an android Phone, here are two things you may like:

### Org-mode <=> Android

First is the MobileOrg app to synchronize your calendar/tasks between your computer org-mode files and your phone. I am using org-mode since a few months, I think I do pretty basics things with it like having a todo list with a deadline for each item. Having it in my phone calendar is a good enhancement. I can also add todo items from my phone to show it on my computer.

The phone and your computer get synced by publishing a special format of org files for the mobile on a remote server. Mobile Org supports ssh, webdav, dropbox or sdcard. I’m using ssh because I own a server and I can reliabily have my things connected together there on a dedicated account. Emacs will then use tramp to publish/retrieve the files.

Official MobileOrg website

### Read/Write sms from a remote place

Second useful thing I like with my android phone is being able to write and send sms (+ some others things but I was most interested by SMS) from my computer. A few services already exists but they work with “cloud” logic and I don’t want my phone to be connected to one more service. The MAXS app provides me what I need : ability to read/write the sms of my phone from the computer without web browser and relying on my own services. MAXS connects the phone to a XMPP account and you set a whitelist of XMPP mails able to send commands, that’s all. Here are a few examples of use:

To write a SMS I just need to speak to the jabber account of my phone and write

sms send firstname lastname  hello how are you ?


Be careful, there are 2 spaces after the lastname ! I think it’s like this so MAXS can make easily the difference between the name and the message.

I can also reply quickly to the last contacted person

reply to Yes I'm answering from my computer


To read the last n sms

sms read n


It’s still not perfect because sometimes it lose connectivity and you can’t speak with it anymore but from the project author it’s not a problem seen on every phone. I did not have the time yet to report exactly the problem (I need to play with Android Debug Bridge for that). If you want to install MAXS, you will need a few app from the store to get it working. First, you will need MAXS main and MAXS transport (a plugin to use XMPP) and then plugins for the differents commands you want, so, maybe, smsread and smswrite. Check their website for more informations.

As presenter earlier on my website, I use profanity as XMPP client. It’s a light and easy to configure/use console client.

Official MAXS Website

# How to kill processes by their name

Written by Solène, on 25 August 2016.
Tags: #system

If you want to kill a process by its name instead of its PID number, which is easier if you have to kill processes from the same binary, here are the commands depending of your operating system:

FreeBSD / Linux

$killall pid_name  OpenBSD $ pkill pid_name


Solaris

Be careful with Solaris killall. With no argument, the command will send a signal to every active process, which is not something you want.

$killall pid_name  # Automatically mute your Firefox tab Written by Solène, on 17 August 2016. Tags: #firefox #web At work I have the sound of my laptop not muted because I need sound from time to time. But browsing the internet with Firefox can sometime trigger some undesired sound, very boring in the office. There is the extension Mute Tab to auto-mute a new tab on Firefox so it won’t play sound. The auto-mute must be activated in the plugin options, it’s un-checked by default. You can find it here, no restart required: Firefox Mute Tab addon I also use FlashStopper which block by default flash and HTML5 videos, so you can click on it to activate them, it doesn’t autoplay. Firefox FlashStopper addon # Port of the week : pwgen Written by Solène, on 12 August 2016. Tags: #security #portoftheweek I will talk about security/pwgen for the current port of the week. It’s a very light executable to generate passwords. But it’s not just a dumb password generator, it has options to choose what kind of password you want. Here is a list of options with their flag, you will find a lot more in the nice man page of pwgen: • -A : don’t use capital letters • -B : don’t use characters which could be missread (O/0, I/l/1 …) • -v : don’t use vowels • etc… You can also use a seed to generate your “random” password (which aren’t very random in this case), you may need it for some reason to be able to reproduce password you lost for a ftp/http access for example. Example of pwgen output generating 5 password of 10 characters. Using –1 parameter so it will only display one password per line, otherwise it display a grid (on column and multiple lines) of passwords. $ pwgen -1 10 5
fohchah9oP
haNgeik0ee
meiceeW8ae
OReejoi5oo
ohdae2Eisu


# Website now compatible gopher !

Written by Solène, on 11 August 2016.
Tags: #gopher #network #lisp

My website is now available with Gopher protocol ! I really like this protocol. If you don’t know it, I encourage you reading this page : Why is Gopher still relevant?.

This has been made possible by modifying the tool generating the website pages to make it generating gopher compatible pages. This was a bit of work but I am now proud to have it working.

I have also made a “big” change into the generator, it now rely on a “markdown-to-html” tool which sadden me a bit. Before that, I was using ham-mode in emacs which was converting html on the fly to markdown so I can edit in markdown, and was exporting into html on save. This had pros and cons. Nothing more than a lisp interpreter was needed on the system generating the files, but I was sometimes struggling with ham-mode because the conversion was destructive. Multiple editing in a row of the same file was breaking code blocks, because it wasn’t exported the same way each time until it wasn’t a code block anymore. There are some articles that I update sometimes to keep it up-to-date or fix an error in it, and it was boring to fix the code everytime. Having the original markdown text was mandatory for gopher export, and is now easier to edit with any tool.

There is a link to my gopher site on the right of this page. You will need a gopher client to connect to it. There is an android client working, also Firefox can have an extension to become compatible (gopher support was native before it have been dropped). You can find a list of clients on Wikipedia.

Gopher is nice, don’t let it die.

# Port of the week : feh

Written by Solène, on 08 August 2016.
Tags: #portoftheweek

Today I will talk about graphics/feh, it’s a tool to view pictures and it can also be used to set an image as background.

I use this command line, invoked by stumpwm when my session starts so I can a nice background with cubes :)

feh --bg-scale /home/solene/Downloads/cubes.jpg


feh as a lot of options and is really easy to use, I still prefer sxiv for viewing but I use feh for my background.

# Port of the week : Puddletag

Written by Solène, on 20 July 2016.
Tags: #portoftheweek #audio #gui

If you ever need to modify the tags of your music library (made of MP3s) I would recommend you audio/puddletag. This tool will let you see all your music metadata like a spreadsheet and just modify the cells to change the artist name, title etc… You can also select multiple cells and type one text and it will be applied on all the selected cells. There is also a tool to extract data from the filename with a regex. This tool is very easy and pleasant to use.

There is an option in the configuration panel that is good to be aware of, by default, when you change the tag of a file, the modification time isn’t changed, so if you use some kind of backup relying on the modification time it won’t be synchronized. In the configuration panel, you will find an option to check which will bump the modification timestamp when you change a tag on a song.

# Port of the week : Profanity

Written by Solène, on 12 July 2016.
Tags: #portoftheweek #network

Profanity is a command-line ncurses based XMPP (Jabber) client. It’s easy to use and seem inspired from irssi for the interface. It’s available in net/profanity.

It’s really easy to use and the documentation on its website is really clear.

To log-in, just type /connect myusername@mydomain and after the password prompt, you will be connected. Easy.

Profanity official website

# Stop being tracked by Google search with Firefox

Written by Solène, on 04 July 2016.
Tags: #security #firefox #web

When you use google search and you click on a link, you a redirected on a google server that will take care of saving your navigation choice from their search engine into their database.

2. This slow the process of using the search engine because you have a redirection (that you don’t see) when you want to visit a link

There is a firefox extension that will fix the links in the results of the search engine so when you click, you just go on the website without saying “hello Google I clicked there”: Google Search Link Fix

You can also use another web engine if you don’t like Google. I keep it because I have best results when searching technical. I tried to use Yahoo, Bing, Exalead, Qwant, Duck duck go, each one for a few days and Google has the bests results so far.

# Port of the week : OpenSCAD

Written by Solène, on 04 July 2016.
Tags: #portoftheweek #3d

OpenSCAD is a software for creating 3D objects like a programming language, with the possibility to preview your creation.

I am personaly interested in 3D things, I have been playing with 3ds Max and Blender for creating 3d objects but I never felt really comfortable with them. I discovered pov-ray a few years ago which is used to create rendered pictures instead of creating objects. Pov-ray use its own “programming language” to describe the scene and make the render. Now, I have a 3D printer and I would like to create things to print, but I don’t like the GUI stuff of Blender and Pov-ray don’t create objects, so… OpenSCAD ! This is the pov-ray of objects !

Here is a simple example that create an empty box (difference of 2 cubes) and a screw propeller:

width = 3;
height = 3;
depth = 6;
thickness = 0.2;

difference() {
cube( [width,depth,height], true);

translate( [0,0,thickness] )
cube( [width-thickness, depth-thickness, height], true);
}

translate( [ width , 0 , 0 ])
linear_extrude(twist = 400, height = height*2)
square(2,true);


The following picture is made from the code above:

There are scad-mode and scad-preview for emacs for editing OpenSCAD files. scad-mode will check the coloration/syntax and scad-preview will create the OpenScad render inside a Emacs pane. Personaly, I use OpenSCAD opened in some corner of the screen with option set to render on file change, and I edit with emacs. Of course you can use any editor, or the embedded editor which is a Scintilla one which is pretty usable.

# Port of the week : arandr

Written by Solène, on 27 June 2016.
Tags: #portoftheweek

Today the Port of the week is x11/arandr, it’s a very simple tool to set-up your screen display when using multiple monitors. It’s very handy when you want to make something complicated or don’t want to use xrandr in command line. There is not much to say because it’s very easy to use!

# Port of the week : x2x

Written by Solène, on 23 June 2016.
Tags: #portoftheweek

Port of the week is now presenting you x2x which stands for X to X connection. This is a really tiny tool in one executable file that let you move your mouse and use your keyboard on another X server than yours. It’s like the other tool synergy but easier to use and open-source (I think synergy isn’t open source anymore).

If you want to use the computer on your left, just use the following command (x2x must be installed on it and ssh available)

$ssh -CX the_host_address "x2x -west -to :0.0"  and then you can move your cursor to the left of your screen and you will see that you can use your cursor or type with the keyboard on your other computer ! I am using it to manage a wall of screen made of raspberry Pi first generation. I used to connect to it with VNC but it was very very slow. # Git cheat sheet Written by Solène, on 08 June 2016. Tags: #cheatsheet #git Here is my git cheat sheet ! Because I don’t like git I never remember how to do X or Y with it so I need to write down simple commands ! (I am used to darcs and mercurial but with the “git trend” I need to learn it and use it). ### Undo uncommited changes on a tracked file $ git reset --hard


$git pull  ### Make a commit containing all tracked files $ git commit -m "Commit message" -a


$git push  # How to send html signature in mu4e Written by Solène, on 07 June 2016. Tags: #email #emacs I switched to mu4e to manage my mails at work, and also to send mails. But in our corporation we all have a signature that include our logo and some hypertext links, so I couldn’t just insert my signature and be done with that. There is a simple way to deal with this problem, I fetched the html part of my signature (which include an image in base64) and pasted it into my emacs config file this way. (setq mu4e-compose-signature "<#part type=text/html><html><body><p>Hello ! I am the html signature which can contains anything in html !</p></body></html><#/part>" )  I pasted my signature instead of the hello world text of course, but you only have to use the part tag and you are done ! The rest of your mails will be plain text, except this part. # My Stumpwm config on OpenBSD Written by Solène, on 06 June 2016. Tags: #openbsd #freebsd #wm #lisp #stumpwm I want to talk about stumpwm, a window manager written in Common LISP. I think one must at least like emacs to like stumpwm. Stumpwm is a tiling window manager one which you create “panes” on the screen like windows on Emacs. A single pane takes 100% of the screen, then you can split it into 2 panes vertically or horizontally and resize it, and you can split again and again. There is no “automatic” tiling. By default, if you have ONE pane, you will only have ONE window displayed, this is a bit different that others tiling wm I had tried. Also, virtual desktops are named groups, nothing special here, you can create/delete groups and rename it. Finally, stumpwm is not minimalistic. To install it, you need to get the sources of stumpwm, install a common lisp interpreter (sbcl, clisp, ecl etc…), install quicklisp (which is not in packages), install the quicklisp packages cl-ppcre and clx and then you can compile stumpwm, that will produce a huge binary which embedded a common lisp interpreter (that’s a way to share common lisp executables, the interpreter can create an executable from itself and include the files you want to execute). I would like to make a package for OpenBSD but packaging quicklisp and its packages seems too difficult for me at the moment. Here is my config file in ~/.stumpwmrc. Updated: 23th january 2018 (defun chomp(text) (subseq text 0 (- (length text) 1))) (defmacro cmd(command) (progn (:eval (chomp (stumpwm:run-shell-command ,,command t))))) (defun get-latence() (let ((now (get-universal-time))) (when (> (- now *latence-last-update* ) 30) (setf *latence-last-update* now) (when (probe-file "/tmp/latenceresult") (with-open-file (x "/tmp/latenceresult" :direction :input) (setf *latence* (read-line x)))))) *latence*) (defvar *latence-last-update* (get-universal-time)) (defvar *latence* "nil") (set-module-dir "~/dev/stumpwm-contrib/") (stumpwm:run-shell-command "setxkbmap fr") (stumpwm:run-shell-command "feh --bg-fill red_damask-wallpaper-1920x1080.jpg") (defvar color1 "#886666") (defvar color2 "#222222") (setf stumpwm:*mode-line-background-color* color2 stumpwm:*mode-line-foreground-color* color1 stumpwm:*mode-line-border-color* "#555555" stumpwm:*screen-mode-line-format* (list "%g | %v ^>^7 %B | " '(:eval (get-latence)) "ms %d ") stumpwm:*mode-line-border-width* 1 stumpwm:*mode-line-pad-x* 6 stumpwm:*mode-line-pad-y* 1 stumpwm:*mode-line-timeout* 5 stumpwm:*mouse-focus-policy* :click ;;stumpwm:*group-format* "%n·%t stumpwm:*group-format* "%n" stumpwm:*time-modeline-string* "%H:%M" stumpwm:*window-format* "^b^(:fg \"#7799AA\")<%25t>" stumpwm:*window-border-style* :tight stumpwm:*normal-border-width* 1 ) (stumpwm:set-focus-color "#7799CC") (stumpwm:grename "Alpha") (stumpwm:gnewbg "Beta") (stumpwm:gnewbg "Tau") (stumpwm:gnewbg "Pi") (stumpwm:gnewbg "Zeta") (stumpwm:gnewbg "Teta") (stumpwm:gnewbg "Phi") (stumpwm:gnewbg "Rho") (stumpwm:toggle-mode-line (stumpwm:current-screen) (stumpwm:current-head)) (set-prefix-key (kbd "M-a")) (define-key *root-map* (kbd "c") "exec urxvtc") (define-key *root-map* (kbd "RET") "move-window down") (define-key *root-map* (kbd "z") "fullscreen") (define-key *top-map* (kbd "M-&") "gselect 1") (define-key *top-map* (kbd "M-eacute") "gselect 2") (define-key *top-map* (kbd "M-\"") "gselect 3") (define-key *top-map* (kbd "M-quoteright") "gselect 4") (define-key *top-map* (kbd "M-(") "gselect 5") (define-key *top-map* (kbd "M--") "gselect 6") (define-key *top-map* (kbd "M-egrave") "gselect 7") (define-key *top-map* (kbd "M-underscore") "gselect 8") (define-key *top-map* (kbd "s-l") "exec slock") (define-key *top-map* (kbd "s-t") "exec urxvtc") (define-key *top-map* (kbd "M-S-RET") "exec urxvtc") (define-key *top-map* (kbd "M-C") "exec urxvtc") (define-key *top-map* (kbd "s-s") "exec /home/solene/dev/screen_up.sh") (define-key *top-map* (kbd "s-Left") "gprev") (define-key *top-map* (kbd "s-Right") "gnext") (define-key *top-map* (kbd "M-ISO_Left_Tab")"other") (define-key *top-map* (kbd "M-TAB") "fnext") (define-key *top-map* (kbd "M-twosuperior") "next-in-frame") (load-module "battery-portable") (load-module "stumptray")  I use a function to get latency from a script that is started every 20 seconds to display the network latency or nil if I don’t have internet access. I use rxvt-unicode daemon (urxvtd) as a terminal emulator, so the terminal command is urxvtc (for client), it’s lighter and faster to load. I also use a weird “alt+tab” combination: • Alt+tab switch between panes • Alt+² (the key above tab) circles windows in the current pane • Alt+Shift+Tab switch to the previous windows selected StumpWM website # Port of the week : mbuffer Written by Solène, on 31 May 2016. Tags: #portoftheweek #network This Port of the week is a bit special because sadly, the port isn’t available on OpenBSD. The port is mbuffer (which you can find in misc/mbuffer). I discovered it while looking for a way to enhance one of my network stream scripts. I have some scripts that get a dump of a postgresql base through SSH, copy it from stdin to a file with tee and send it out to the local postgres, the command line looks like $ ssh remote-base-server "pg_dump my_base | gzip -c -f -" | gunzip -f | tee dumps/my_base.dump | psql my_base


I also use the same kind of command to receive a ZFS snapshot from another server.

But there is an issue, the end server is relatively slow, postgresql and ZFS will eat lot of data from stdin and then it will stop for sometimes writing on the disk, when they are ready to take new data, it’s slow to fill them. This is where mbuffer takes places. This tool permit to add a buffer that will take data from stdin and fill its memory (that you set on the command line), so when the slowest part of the command is ready to take data, mbuffer will empty its memory into the pipe, so the slowlest command isn’t waiting to get filled before working again.

The new command looks like that for a buffer of 300 Mb

ssh remote-base-server "pg_dump my_base | gzip -c -f -" |  gunzip -f | tee dumps/my_base.dump | mbuffer -s 8192 -m 300M | psql my_base


mbuffer also comes with a nice console output, showing

• bandwith in

• bandwith out

• percentage/consumption of memory filled

• total transfered

in @ 1219 KiB/s, out @ 1219 KiB/s, 906 MiB total, buffer 0% full

In this example the server is too fast so there is no wait, the buffer isn’t used (0% full).

mbuffer can also listen on TCP, unix socket and have a lot of parameters that I didn’t try, if you think that can be useful for you, just go for it !

# FreeBSD and Perc H720P Mini raid controller

Written by Solène, on 25 May 2016.
Tags: #freebsd #hardware

I had a problem with my 3 latests R430 Dell server which all have a PERC H730P Mini raid controller. The installer could barely works and slowly, and 2 servers were booting and crashing with FS corruption while the latest just didn’t boot and the raid was cleared.

It is a problem with a driver of the raid controller. I don’t understand exatly the problem but I found a fix.

From man page mfi(4)

A tunable is provided to adjust the mfi driver's behaviour when attaching
to a card.  By default the driver will attach to all known cards with
high probe priority.  If the tunable hw.mfi.mrsas_enable is set to 1,
then the driver will reduce its probe priority to allow mrsas to attach
to the card instead of mfi.


In order to install the system, you have to set hw.mfi.mrsas_enable=1 on the install media, and set this on the installed system before booting it.

There are two ways for that:

• if you use a usb media, you can mount it and edit /boot/loader.conf and add hw.mfi.mrsas_enable=1
• at the boot screen with the logo freebsd, choose 3) Espace to boot prompt, type set hw.mfi.mrsas_enable=1 and boot

You will have to edit /boot/loader.conf to add the line on the installed system from the live system of the installer.

I have been struggling a long before understanding the problem. I hope this message could save time to somebody else.

# Port of the week : rdesktop

Written by Solène, on 20 May 2016.
Tags: #portoftheweek

This week we will have a quick look at the tool rdesktop. Rdesktop is a RDP client (RDP stands for Remote Desktop Protocol) which is used to share your desktop with another machine. RDP is a Microsoft thing and it’s most used on Windows.

I am personally using it because sometimes I need to use Microsoft Word/Excel or Windows only software and I have a dedidated virtual machine for this. So I use rdesktop to connect in fullscreen to the virtual machine and I can work on Windows. The RDP protocol is very efficient, on LAN network there is no lag. I appreciate much more using the VM with RDP than VNC.

You can also have RDP servers within virtual machines. VirtualBox let you have (with an additional package to add on the host) RDP server for a VM. Maybe VmWare provides RDP servers too. I know that Xen and KVM can give access through VNC or Spice but no RDP.

For its usage, if you want to connect to a RDP server whose IP address is 192.168.1.100 in fullscreen with max quality, type:

$ls -a repo2 . .. .git  You may use this one for local use, but you may want to clone it later, and work with this repository and doing push/pull. That’s how gitit works, it has a folder “wikidata” that should be initiated as git, and it will works locally. But if you want to clone it on your computer, work on the documentation and then push your changes to gitit, you may get this error when pushing : ### Problem when pushing I cloned the repository, made changes, committed and now I want to push, but no… Décompte des objets: 3, fait. Écriture des objets: 100% (3/3), 232 bytes | 0 bytes/s, fait. Total 3 (delta 0), reused 0 (delta 0) remote: error: refusing to update checked out branch: refs/heads/master remote: error: By default, updating the current branch in a non-bare repository remote: error: is denied, because it will make the index and work tree inconsistent remote: error: with what you pushed, and will require 'git reset --hard' to match remote: error: the work tree to HEAD. remote: error: remote: error: You can set 'receive.denyCurrentBranch' configuration variable to remote: error: 'ignore' or 'warn' in the remote repository to allow pushing into remote: error: its current branch; however, this is not recommended unless you remote: error: arranged to update its work tree to match what you pushed in some remote: error: other way. remote: error: remote: error: To squelch this message and still keep the default behaviour, set remote: error: 'receive.denyCurrentBranch' configuration variable to 'refuse'. ! [remote rejected] master -> master (branch is currently checked out)  git is unhappy, I can’t push ### Solution You can fix this “problem” by changing a config in the server repository with this command : $ git config --local receive.denyCurrentBranch updateInstead


Now you should be able to push to your non-bare repository.

# Port of the week : sxiv

Written by Solène, on 13 May 2016.
Tags: #portoftheweek

This week I will talk about the command line image viewer sxiv. While it’s a command line tool, of course it spawn a X window to display the pictures. It’s very light and easy of use, it’s my favorite image viewer.

• sxiv file1 file2… : Sxiv open only files given as parameter or filenames from stdin
• p/n : previous/next
• f : fullscreen
• 12 G : go to 12th image of the list
• Return : switch to the thumbnails mode / select the image from the thumbnails mode
• q : quit
• a lot more in the well written man page !

For power users who have a LOT of pictures to sort: Sxiv has a nice function that let you mark images you see and dump the list of marked images in a file (see parameter -o).

Tip for zsh users, if you want to read every jpg files in a tree, you
can use **sxiv **/*.jpg** globbing as seen in the Zsh cheat sheet
).

In OpenBSD ports tree, check graphics/sxiv.

# Port of the week : bwm-ng

Written by Solène, on 06 May 2016.
Tags: #portoftheweek #network

I am starting a periodic posting for something I wanted to do since a long time. Take a port in the tree and introduce it quickly. There are tons of ports in the tree that we don’t know about. So, I will write frequently about ports that I use frequently and that I find useful, if you read this, maybe I will find a new tool to your collection of “useful program”. :-)

For a first one, I would like to present net/bwm-ng. Its name stands for “_BandWitch Monitor next-generation_”, it allows the user to watch in real-time the bandwith usage of the different network interfaces. By default, it will update the display every 0.5 second. You can change the frequency of updating by pressing keys ‘+’ and ‘-’.

Let see the bindings of the interactive mode :

• ‘t’ will cycle between current rate, maximum peak, sum, average on 30 seconds.
• ‘n’ will cycle between data sources, on OpenBSD it defaults to “getifaddrs” and you can also choose “sysctl” or “netstat -i”.
• ‘d’ will change the unit, by default it shows KB but you can change to another units that suits better your current data.

bwm-ng v0.6.1 (probing every 5.700s), press 'h' for help
-         iface                   Rx                   Tx                Total
==============================================================================
lo0:           0.00  B              0.00  B              0.00  B
em0:          19.89 MB            662.82 KB             20.54 MB
pflog0:           0.00  B              0.00  B              0.00  B
------------------------------------------------------------------------------
total:          19.89 MB            662.82 KB             20.54 MB


It’s available on *BSD, Linux and maybe others.

In OpenBSD ports tree, look for net/bwm-ng.

# My mutt cheat sheet

Written by Solène, on 03 May 2016.
Tags: #cheatsheet #mutt #email

I am learning mutt and I am lost. If you are like me, you may like the following cheat sheet!

I am using it through imap, it may be different with local mailbox.

Case is important !

• Change folder : Y
• Filter the display : l (for limit) and then a filter like this
• ~d <2w : ~d for date and <2w for “less than 2 weeks” no space in <2w !
• ~b “hello mate” : ~b is for body and the string is something to find in the body
• ~f somebody@zxy.abc : ~f for from and you can make an expression
• ~s “Urgent” : ~s stands for subject and use a pattern
• Delete messages with filter : D with a filter, if you used limit before it will propose by default the filter of limit
• Delete a message : d (it will be marked as Deleted)

Deleted messages will be removed when you change the folder or if you exit. Pressing $can do it manually. # My zsh cheat sheet Written by Solène, on 03 May 2016. Tags: #cheatsheet #zsh I may add new things in the future, as they come for me, if I find new features useful. ### How to repeat a command n time repeat 5 curl http://localhost/counter_add.php  ### How to expand recursively If you want to find every file ending by .lisp in the folder and subfolder you can use the following syntax. Using ****** inside a pattern while do a recursive globbing. ls **/*.lisp  ### Work with temp files If you want to work on some command outputs without having to manage temporary files, zsh can do it for you with the following syntax: =(command that produces stdout). In the example we will use emacs to open the list of the files in our personal folder. emacs =(find ~ -type f)  This syntax will produce a temp file that will be removed when emacs exits. ### My ~/.zshrc here is my ~/.zshrc, very simple (I didn’t pasted the aliases I have), I have a 1000 lines history that skips duplicates. HISTFILE=~/.histfile HISTSIZE=1000 SAVEHIST=1000 setopt hist_ignore_all_dups setopt appendhistory bindkey -e zstyle :compinstall filename '/home/solene/.zshrc' autoload -Uz compinit compinit export LANGUAGE=fr_FR.UTF-8 export LANG=fr_FR.UTF-8 export LC_ALL=fr_FR.UTF-8 export LC_CTYPE=fr_FR.UTF-8 export LC_MESSAGES=fr_FR.UTF-8  # Simple emacs config Written by Solène, on 02 May 2016. Tags: #emacs #cheatsheet Here is a dump of my emacs config file. That may be useful for some emacs users who begin. If you doesn’t want to have your_filename.txt~ files with a tilde at the end (this is a default backup file), add this ; I don't want to have backup files everywhere with filename~ name (setq backup-inhibited t) (setq auto-save-default nil)  To have parenthesis highlighting on match, which is very useful, you will need this ; show match parenthesis (show-paren-mode 1)  I really like this one. It will save the cursor position in every file you edit. When you edit it again, you start exactly where you leaved the last time. ; keep the position of the cursor after editing (setq save-place-file "~/.emacs.d/saveplace") (setq-default save-place t) (require 'saveplace)  If you write in utf–8 (which is very common now) you should add this. ; utf8 (prefer-coding-system 'utf-8)  Emacs modes are used depending on the extension of a file. Sometime you need to edit files with a custom extension but you want to use a mode for it. So, you just need to add some line like this to get your mode automatically when you load the file. ; associate extension - mode (add-to-list 'auto-mode-alist '("\\.md\\'" . markdown-mode)) (add-to-list 'auto-mode-alist '("\\.tpl$" . html-mode))


My Org-mode part in the config file

(require 'org)
(define-key global-map "\C-ca" 'org-agenda)
(setq org-log-done t)
(setq org-agenda-files (list "~/Org/work.org" "~/Org/home.org"))


Stop mixing tabs and space when indenting

(setq indent-tabs-mode nil)


# How to add a route through a specific interface on FreeBSD

Written by Solène, on 02 May 2016.
Tags: #freebsd #network

If someday under FreeBSD you have a system with multiple IP address on the same network and you need to use a specific IP for a route, you have to use the -ifa parameter in the route command.

In our example, we have to use the address 192.168.1.140 to access the network 192.168.30.0 through the router 192.168.1.1, this is as easy as the following.

route add -net 192.168.30.0 192.168.1.1 -ifa 192.168.1.140
`

You can add this specific route like any other route in your rc.conf as usual, just add the -ifa X.X.X.X parameter.

# What it this blog?

Written by Solène, on 29 April 2016.
Tags: #lisp #cl-yag

This website is generated using cl-yag, which I am the author.

I have some work to do to cl-yag but I want to keep it relatively easy to use and clean

# Todo

• less code : that should be possible and an interesting task
• tests to check if modifying don’t break anything (but I have no idea how to do that)

# Done

• Host it on github with default settings
• Permit to type A
• Right panel
• Make the code easier with macros
• Find a way to use markdown