Forget what directory you are in? Type pwd.

Ever wonder what those numbers after command names were, as in cat(1)? It’s the section of the manual the man page is in. man man will tell you more.

Any user that is a member of the wheel group can use su - to simulate a root login. You can add a user to the wheel group by editing /etc/group.

You can use aliases to decrease the amount of typing you need to do to get commands you commonly use. Examples of fairly popular aliases include (in Bourne shell style, as in /bin/sh, bash, ksh, and zsh): alias lf=”ls -FA” alias ll=”ls -lA” alias su=”su -m” In csh or tcsh, these would be alias lf ls -FA alias ll ls -lA alias su su -m To remove an alias, you can usually use ‘unalias aliasname’. Read more