Scripting

Set the PATH manually in your script

Set the IFS manuall: IFS=' '

set -o noglob switch off filename expansion

set -o noglob switch off filename expansion

Use unset for every variable before you use it.

Check every argument to see if it meets the required specifications: user=${1##*[ \\$/;()|\>\<& ]}

Do not use eval in your scripts

Before you create a file, add a trap on EXIT to delete it if the script aborts

Do not use temporary files!

Arguments

The 10th argument: ${10} NOT $10!!!

Setting the arguments new: set foo bar

Setting arguments with "-" set --foo

Deleting all old arguments set --

Backquotes

command1 ${comand2} executes command2 and uses the return value to start command1