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{{tag>Bash Script Console}}

Voir :
* https://google.github.io/styleguide/shellguide.html
* https://github.com/google/styleguide/blob/gh-pages/shellguide.md
* http://www.kfirlavi.com/blog/2012/11/14/defensive-bash-programming
* http://www.linuxjournal.com/content/working-functions-towers-hanoi
* https://github.com/icy/bash-coding-style
* http://redsymbol.net/articles/unofficial-bash-strict-mode/
* http://mywiki.wooledge.org/BashFAQ/105
* https://blog.yossarian.net/2020/01/23/Anybody-can-write-good-bash-with-a-little-effort
* https://github.com/icy/bash-coding-style?tab=readme-ov-file#deprecation
* https://www.reddit.com/r/linuxadmin/comments/9x1ist/what_are_your_conventions_with_bashshell_scripts/
* https://www.linkedin.com/pulse/bash-scripting-conventions-engin-polat
* https://gist.github.com/the-glima/39905476c82a8acf9c81b7cfe08e5f03
* https://github.com/chenkaie/junkcode/blob/master/bash/Defensive-BASH-Programming.sh
* https://bertvv.github.io/cheat-sheets/Bash.html
* https://medium.com/better-programming/defensive-programming-to-create-a-robust-ish-shell-script-d9f21292d08a
* https://frippertronics.com/posts/defensive_bash_programming.html
* https://blog.seboss666.info/2020/04/programmation-defensive-en-bash/
* https://devhints.io/bash
* https://kvz.io/blog/bash-best-practices.html & https://github.com/kvz/bash3boilerplate/
* http://unix.stackexchange.com/questions/8759/best-practice-to-use-in-bash




= Bash Les bonnes pratiques

Faire des tests unitaires avec bats

== Les pièges 

<code bash>
rm -rf $var1/$var2
</code>

Si ''$var1'' et ''$var2'' sont vides on un un jolie 

Solution : nounset

<code bash>
#! /bin/bash
set -o nounset
</code>

et quand nécessaire utiliser
<code bash>
[ -z "${foo:-}" ]
</code>

Don’t use:
<code bash>
  cd "${foo}"
  [...]
  cd ..
</code>
but
<code bash>
  (
    cd "${foo}"
    [...]
  )
</code>
Voir https://bertvv.github.io/cheat-sheets/Bash.html

== Les forks bombes

.bashrc
newgrp

Solution [[ulimit]]

Voir
 


== Les tubes nommés (pipes)

Source : https://blog.g3rt.nl/retain-exit-status-code-through-pipe.html

FIXME : traduire en Français

How to retain exit status codes through pipes in Bash scripts

Suppose you have a line

<code bash>
mysqldump | pigz
</code>

in your script. Then the exit status code will be of gzip, rather than mysqldump, while the most likely process to fail here is mysqldump.

To fix this, add this at the top of your bash scripts:
<code bash>
set -o pipefail
</code>

== Arrêt du script lors de la moindre erreur

Voir http://redsymbol.net/articles/unofficial-bash-strict-mode/

<code bash>
set -euo pipefail
</code>

<code bash>
#!/bin/bash
set -euo pipefail
IFS=$'\n\t'
</code>

== if $? SC2181

Source : https://www.shellcheck.net/wiki/SC2181

Code problématique 
<code bash>
make mytarget

if [ $? -ne 0 ]
then
  echo "Build failed"
fi
</code>

Code Correct
<code bash>
if ! make mytarget;
then
  echo "Build failed"
fi
</code>




== Test

https://github.com/chriscool/sharness



== Conventions de nommage



Environment variables or shell variables introduced by the operating system, shell startup scripts, or the shell itself, etc., are usually all in CAPITALS1.

To prevent your variables from conflicting with these variables, it is a good practice to use lower_case variable names.


== Autres

A la place de mkdir, privilégier ''install -d''

<code bash>
#mkdir /tmp/plop
install -d /tmp/plop
</code> 


Préférer un ''unlink'' à ''rm'' pour supprimer un  lien symbolique