Bash Alias

Expansion

The first token of a command is tested for equality to any existing aliases. If it matches, that token is replaced with the literal content of the alias, including any control characters.

After alias expansion succeeds, the first token is again tested for equality to any existing aliases. If it matches a new alias, that token is again replaced. On the other hand, an alias is not re-expanded even if it matches again.

If an alias's value contains a trailing space character, the next token also undergoes alias expansion.

Aliases are created and removed with the alias and unalias builtins. It is important to quote the value of an alias.

Usage

The repeated expansion properties of aliases enable a form of inheritance.

Consider the following aliases:

alias ls='ls -F'
alias la='ls -A'
alias ll='la -l'

In this environment, ll will execute as ls -F -A -l.

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