Here's a small tip for Unix and Linux developers and IT pros: Want to run the same command again at the terminal? In most modern shells (tcsh, zsh, bash), you can simply type "!!".

For example, say you forget to use sudo:
yum upgrade -y
pkg upgrade -y

Instead of typing the whole command again, just do this:
sudo !!

This is a lifesaver for longer commands. Give it a try!