The alias command is used to create a command that will invoke another command. In this example, the dte command will invoke the date command.
The user command now returns whoami.
~]$ user john.doe
The unalis command can be used to remove the alias.
The alias command will not survive when the user logs out or the system is restarted. To create a permanent alias, the alias would need to be created in /home/username/.bash_profile, like this.
alias user=whoami export alias