Bash Tricks

Bash.md

• $$ is the process ID (PID) of the script itself.
• $! gives the process id of the most recently executed background process.
• $? Stores the exit value of the last command that was executed.
• $# is the special parameter in which bash gives the number of positional parameter in decimal.
• $@ Stores all the arguments that were entered on the command line, individually quoted ("$1" "$2" ...).
• $* Stores all the arguments that were entered on the command line ($1 $2 ...).
• $_ The underscore variable is set at shell startup and contains the absolute file name of the shell or script being executed as passed in the argument list.
• https://javarevisited.blogspot.com/2011/06/special-bash-parameters-in-script-linux.html
• https://devhints.io/bash
• https://www.tecmint.com/useful-tips-for-writing-bash-scripts-in-linux/