See the built-in command description in the appropriate shell manual page.
Shell builtin commands are commands that can be executed within the
running shell's process.
Note that, in the case of
builtin commands, the command is executed in a subshell if it occurs as
any component of a pipeline except the last.
If a command specified to the shell contains a slash
the shell will not execute a builtin command, even if the last component
of the specified command matches the name of a builtin command.
Thus, while specifying
causes a builtin command to be executed under shells that support the
While some builtin commands may exist in more than one shell, their
operation may be different under each shell which supports them.
Below is a table which lists shell builtin commands, the standard shells
that support them and whether they exist as standalone utilities.
Only builtin commands for the
shells are listed here.
Consult a shell's manual page for
details on the operation its builtin commands.
Beware that the
manual page, at least, calls some of these commands
and some of them
Users of other shells may need to consult an
page or other sources of documentation.
do exist externally,
but are implemented as scripts using a builtin command of the same name.