Some things you can do with bash scripting and a bit of glue closely resemble magic. While often not usable outside a very specific use case, shell scripts can do things in amazingly cool ways with less code. If you are using any clever shell scripts that do something useful, or you just want to show off your applied geekdom, post your script here.
Because shell scripts can use a very compact syntax to execute complex tasks - please be sure you do understand what the script is supposed to do before executing it! Do not simply copy'n'paste code from this site! You can learn (a lot!) more about shell scripting from the Advanced Bash-Scripting Guide.