true, false - return exit status zero or one respectively
The command does nothing, and returns exit code zero. The command does
nothing, and returns exit code one. They are typically used to con‐
struct command procedures.
Exit values are:
This command loop repeats without end:
is typically used in shell scripts. Some shells provide a built-in
version of (and that is more efficient than the standalone versions.
SEE ALSOcsh(1), ksh(1), sh(1), sh-posix(1).