Looking for Wisdom about Bash¶

To be sorted¶

• About Bash completion, Dmitry’s post

Bash programming¶

• BASH Programming - Introduction HOW-TO
• Advanced Bash-Scripting Guide
• Defensive BASH Programming Read the comments!
• Learning bash scripting for beginners Twitter: https://twitter.com/nixcraft

Bash error handling¶

• ! https://stackoverflow.com/questions/64786/error-handling-in-bash/69808#69808
• https://serverfault.com/questions/143445/what-does-set-e-do-and-why-might-it-be-considered-dangerous

Bash Solutions¶

• Make sure, the shell is Bash:

  test "$SHELL" = "/bin/bash" && echo true
  

• Dmitry Dulepov: Set environment variable when “cd”ing to the directory

  set_enviroment_variable_per_dir_in_bash.sh:

  # Note: this is just a fragment that you should put in your ~/.bash_profile
  # Tested on Mac only!
  #
  # If you want a more sophisticated and feature rich solution here are some pointers:
  # - https://github.com/cxreg/smartcd
  # - http://swapoff.org/ondir.html
  
  function cd_ {
          if [ -e .env_off ] ; then
                  . .env_off
          fi
          builtin cd "$*"
          if [ -e .env ] ; then
                  . .env
          fi
  }
  
  alias cd=cd_
  

• @nixcraft@Twitter:

  Problematic shell code:

  cd dir
  rm -r *.py
  

  Good code:

  cd dir || exit
  rm -r *.py
  

  Even better:

  [ -d "dir" ] && rm -r *.py
  

Bash Testing¶

• Testing
• File test operators
• Other test operators

ZSH¶

sudo apt-get install zsh

Solutions¶

echo $PATH | tr ":" "\n"

#!/usr/bin/env bash
arr=$(echo $PATH | tr ";" "\n")
for part in $arr
do
   echo "$part"
done