alias saves time by creating a shortcut to an existing command or chain of commands.
alias shortcut='echo hello'
Typing shortcut is now the same as running echo hello.
Running alias in the command window creates a temporary alias. This alias no longer exists in a new session. To create a permanant alias, edit your .bashrc file. Add the same command as you would type in the command window to the end of the file. You can now always run that command in your bash terminal.
To remove a temporary alias, run the command unalias [SHORTCUT_NAME] Using -a in place of the shortcut name will remove all aliases.
unalias shortcut
shortcut no longer works as a command.
unalias -a
all temporary aliases are erased.