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/* tty -- print the path of the terminal connected to standard input
Copyright (C) 1990, 1991 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/* Displays "not a tty" if stdin is not a terminal.
Displays nothing if -s option is given.
Exit status 0 if stdin is a tty, 1 if not, 2 if usage error,
3 if write error.
Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#include "system.h"
#include "version.h"
void error ();
static void usage ();
/* The name under which this program was run. */
char *program_name;
/* If nonzero, return an exit status but produce no output. */
static int silent;
/* If non-zero, display usage information and exit. */
static int show_help;
/* If non-zero, print the version on standard output and exit. */
static int show_version;
static struct option const longopts[] =
{
{"help", no_argument, &show_help, 1},
{"silent", no_argument, NULL, 's'},
{"quiet", no_argument, NULL, 's'},
{"version", no_argument, &show_version, 1},
{NULL, 0, NULL, 0}
};
void
main (argc, argv)
int argc;
char **argv;
{
char *tty;
int optc;
program_name = argv[0];
silent = 0;
while ((optc = getopt_long (argc, argv, "s", longopts, (int *) 0)) != EOF)
{
switch (optc)
{
case 0:
break;
case 's':
silent = 1;
break;
default:
usage ();
}
}
if (show_version)
{
printf ("%s\n", version_string);
exit (0);
}
if (show_help)
usage ();
if (optind != argc)
usage ();
tty = ttyname (0);
if (!silent)
{
if (tty)
puts (tty);
else
puts ("not a tty");
if (ferror (stdout) || fclose (stdout) == EOF)
error (3, errno, "standard output");
}
exit (isatty (0) ? 0 : 1);
}
static void
usage ()
{
fprintf (stderr, "\
Usage: %s [-s] [--silent] [--quiet]\n", program_name);
exit (2);
}
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