/* See LICENSE file for copyright and license details. */ #include <stdio.h> #include <unistd.h> #include "util.h" static void usage(void) { eprintf("usage: %s\n", argv0); } int main(int argc, char *argv[]) { char *tty; ARGBEGIN { default: usage(); } ARGEND; tty = ttyname(STDIN_FILENO); puts(tty ? tty : "not a tty"); return tty ? 0 : 1; }