src/tty.c

   1 /* tty -- print the path of the terminal connected to standard input
   2    Copyright (C) 90, 91, 92, 93, 94, 95, 1996 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Displays "not a tty" if stdin is not a terminal.
  19    Displays nothing if -s option is given.
  20    Exit status 0 if stdin is a tty, 1 if not, 2 if usage error,
  21    3 if write error.
  22
  23    Written by David MacKenzie <djm@gnu.ai.mit.edu>.  */
  24
  25 #include <config.h>
  26 #include <stdio.h>
  27 #include <getopt.h>
  28 #include <sys/types.h>
  29
  30 #include "system.h"
  31 #include "error.h"
  32
  33 static void usage __P ((int status));
  34
  35 /* The name under which this program was run. */
  36 char *program_name;
  37
  38 /* If nonzero, return an exit status but produce no output. */
  39 static int silent;
  40
  41 /* If nonzero, display usage information and exit.  */
  42 static int show_help;
  43
  44 /* If nonzero, print the version on standard output and exit.  */
  45 static int show_version;
  46
  47 static struct option const longopts[] =
  48 {
  49   {"help", no_argument, &show_help, 1},
  50   {"silent", no_argument, NULL, 's'},
  51   {"quiet", no_argument, NULL, 's'},
  52   {"version", no_argument, &show_version, 1},
  53   {NULL, 0, NULL, 0}
  54 };
  55
  56 int
  57 main (int argc, char **argv)
  58 {
  59   char *tty;
  60   int optc;
  61
  62   program_name = argv[0];
  63   setlocale (LC_ALL, "");
  64   bindtextdomain (PACKAGE, LOCALEDIR);
  65   textdomain (PACKAGE);
  66
  67   silent = 0;
  68
  69   while ((optc = getopt_long (argc, argv, "s", longopts, (int *) 0)) != EOF)
  70     {
  71       switch (optc)
  72         {
  73         case 0:
  74           break;
  75
  76         case 's':
  77           silent = 1;
  78           break;
  79
  80         default:
  81           usage (2);
  82         }
  83     }
  84
  85   if (show_version)
  86     {
  87       printf ("tty (%s) %s\n", GNU_PACKAGE, VERSION);
  88       exit (0);
  89     }
  90
  91   if (show_help)
  92     usage (0);
  93
  94   if (optind != argc)
  95     usage (2);
  96
  97   tty = ttyname (0);
  98   if (!silent)
  99     {
 100       if (tty)
 101         puts (tty);
 102       else
 103         puts (_("not a tty"));
 104
 105       if (ferror (stdout) || fclose (stdout) == EOF)
 106         error (3, errno, _("standard output"));
 107     }
 108
 109   exit (isatty (0) ? 0 : 1);
 110 }
 111
 112 static void
 113 usage (int status)
 114 {
 115   if (status != 0)
 116     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 117              program_name);
 118   else
 119     {
 120       printf (_("Usage: %s [OPTION]...\n"), program_name);
 121       printf (_("\
 122 Print the file name of the terminal connected to standard input.\n\
 123 \n\
 124   -s, --silent, --quiet   print nothing, only return an exit status\n\
 125       --help              display this help and exit\n\
 126       --version           output version information and exit\n\
 127 "));
 128       puts (_("\nReport bugs to sh-utils-bugs@gnu.ai.mit.edu"));
 129     }
 130   exit (status);
 131 }