A command abbreviation is called alias. To create or delete an alias is performed by the alias and unalias commands.

By default, alias gives a list of the current aliases.

alias [name[=value]]
alias ls
alias ls="ls -l"

If a command is aliased, the prefix \ returns to the initial state.

Before searching a command in the PATH directories, the shell looks if an alias of the command exists and executes it first. The prefix \ inhibits the use of the alias.