Using an Android Device as a Second Monitor on *nix
Using X forwarding sending an application over to an Android device is relatively painless.
Linux
Get Your External IP Address From the CLI
How to get your external IP address on the CLI.
Delete All Files Except for a Particular Extension
How to delete all the files in the current directory except for files of a certain extension.
Copy and Paste to and From the Clipboard in the CLI
How to copy and paste to and from the clipboard while working in the CLI.