Bash Builtin Commands

The set of portable commands.

Commands

Builtin

builtin can be useful to call a builtin command when there is a custom command with the same name.

Cd

Calling cd without an argument is the same as cd ~.

cd - changes the current working directory to the previous working directory.

Command

command can be useful to call a command when there is a function with the same name.

command is also commonly used to determine if a command is locally available.

if ! command -v mypy >/dev/null 2>&1; then
  echo "cannot locate mypy; is it installed?"
  exit
fi

Declare

When used within a function definition, the variable is set to local scope.

To create a variable that is marked for export, use:

declare -x myvar

To create a variable that is marked for tracing, use:

declare -t myvar

To create a read-only constant, use:

declare -r myconst

To create an integer variable, use:

declare -i myinteger

To create an array, use:

declare -a myarray

To create an associative array, use:

declare -A myarray

With some exceptions, these options can be combined. Additionally, options can be explicitly disabled by substituting the dash (-) with a plus sign (+).

Reserved Keywords

Some parts of the language are technically implemented as a command.

See here for break and continue.

See here for return.

See here for compgen, complete, and compopt`.

See here for bg, coproc, fg, and jobs.

CategoryRicottone