16.2 true: Do nothing, successfully

true does nothing except return an exit status of 0, meaning success. It can be used as a place holder in shell scripts where a successful command is needed, although the shell built-in command : (colon) may do the same thing faster. In most modern shells, true is a built-in command, so when you use `true' in a script, you're probably using the built-in command, not the one documented here.

By default, true honors the `--help' and `--version' options. However, that is contrary to POSIX, so when the environment variable POSIXLY_CORRECT is set, true ignores all command line arguments, including `--help' and `--version'.

This version of true is implemented as a C program, and is thus more secure and faster than a shell script implementation, and may safely be used as a dummy shell for the purpose of disabling accounts.