alias
also: bash alias, shell alias
A user-defined shortcut that maps a custom name to a command or series of commands. Aliases let you create abbreviated or alternative names for frequently used commands.
An alias is a way to create a custom name for a command or command sequence in your shell. When you type the alias name, the shell substitutes and executes the associated command(s) instead. This saves typing and makes complex commands easier to remember.
Aliases are typically defined using the alias builtin command. For example, alias ll='ls -lah' creates a shortcut named ll that runs ls -lah (a detailed file listing). After defining this, typing ll is equivalent to typing the full command.
To make aliases persist across shell sessions, add them to your shell's configuration file (such as ~/.bashrc for Bash or ~/.zshrc for Zsh). You can view existing aliases with the alias command (no arguments), and remove one with unalias alias_name.
Aliases are most useful for commands you run frequently, but they cannot accept arguments in flexible ways—for more complex shortcuts, shell functions are often better suited.