If you use the Linux command line interface, here’s a link to a large collection of handy shortcuts:
www.commandlinefu.com/commands/browse/sort-by-votes
Some examples from the site:
sudo !!
Useful when you forget to use sudo for a command. “!!” grabs the last run command.
'ALT+.' or '<ESC> .'
Place the argument of the most recent command on the shell.
When typing out long arguments, such as: cp file.txt /var/www/wp-content/uploads/2009/03/
You can put that argument on your command line by holding down the ALT key and pressing the period ‘.’ or by pressing Escape then the period ‘.’. For example: cd 'ALT+.'
mount | column -t
currently mounted filesystems in a nice layout.
man ascii
When you need quick access to the ASCII table
ctrl-l
Clear the terminal screen.
(cd /tmp && ls)
Jump to a directory, execute a command and jump back to current dir
disown -a && exit
Close shell keeping all subprocesses running