#Show all the available paths
chrisaiv$ echo $PATH

#Just for the BASH shell
chrisaiv$ ~/.bash_profile

#.profile is for all shells
chrisaiv$ .profile

#List all files and make it look pretty
alias ll="ls -lahG"

             #1             #2              #3                  #4 (Existing Paths)
export PATH="/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:$PATH"

For starters, BASH is an acronym meaning Born Again Shell.  $PATH are the places where it will look for commands and in the order in which they are placed.

Bash: $PATH explained!

Bash