You need to make sure that there are no malicious aliases in your environment for security reasons.

Use the unalias-a command to unalias any existing aliases.

If an attacker can trick root or even another user into running a command, they will be able to gain access to data or privileges they shouldn’t have. One way to trick another user into running a malicious program is to create an alias to some other common program (e.g., ls).

The leading , which suppresses alias expansion, is very important because without it you can do evil things like this:

$ alias unalias=echo
$ alias builtin=ls

$ builtin unalias vi
ls: unalias: No such file or directory
ls: vi: No such file or directory

$ unalias -a
-a