The ‘alias’ command in CentOS allows for you to create an alias to a command. For example, if you want to use the vim text editor, but are used to typing vi file-to-edit.txt, you can create an alias to automatically start vim instead of vi when typing the command.
To show the currently configured aliases for your shell simply type ‘alias’ with no arguments.
To set an alias to use vim for when vi is typed the following syntax would be used.
To remove an alias you use the unalias command, for example to remove the previous vi to vim example you would type.
Those are the basics of the command, for more info see the manpage.