Bash

  • ss64.com/bash - well-written compilation of command references.
  • command-not-found.com - for those times when the command is not found. Enter the command and it will tell you how to install the tool in a range of operating systems.
  • explainshell.com - explains shell commands by breaking them apart.
  • tldr.sh - a neat alternative to raw man pages.
  • linuxcommand.org - linux command line and shell scripting guide.
  • #bash FAQ - tips compiled from the #bash Freenode IRC channel.

Shell scripting