env
View environment variables for the current shell
export
Allow child shell sessions to use an environment variable
set
By default dieplay all bash environment settings, veriables and functions. Also, it is used to enable and disable bash settings.
unset
Remove of an environment variable alogs with it's value
alias
Used to create a shortcuts to a longer command, typically with options
function
It is a bash function keyword that it is any custom list of commands that user can use in bash shell
. (dot character) or source
parse or apply settings from a file into the current bash session or script
PATH environment variable
environment variable that defines where application can be found by the bash shell without specifying their full path