Run a shell builtin, passing it args, and return its exit status.
builtin [shell-builtin [args]]
This is useful when defining a shell function with the same name as a shell builtin, retaining the functionality of the builtin within the function.
For example, to write a function to replace `cd’
that writes the hostname and current directory
to an xterm title bar:
builtin cd “$@” && xtitle “$HOST: $PWD”
The return status is non-zero if shell-builtin is not a shell builtin command.