Where do I find things ?
If you are trying to find a program, log into the shell. Typing whereis program (where "program" is the program you are looking for) will show you one or more matches for what you are looking for.
If you have more than one copy of a program, say one in /usr/bin and another in /usr/local/bin/, typing which program will show you which one will be called first. If you can't find it at all, typing locate program will show you every file that matches "program." Some of the most common programs are: