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130 lines
2.9 KiB
C
130 lines
2.9 KiB
C
/* tty -- print the path of the terminal connected to standard input
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Copyright (C) 90, 91, 92, 93, 1994 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* Displays "not a tty" if stdin is not a terminal.
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Displays nothing if -s option is given.
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Exit status 0 if stdin is a tty, 1 if not, 2 if usage error,
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3 if write error.
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Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
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#include <config.h>
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#include <stdio.h>
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#include <getopt.h>
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#include <sys/types.h>
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#include "system.h"
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#include "version.h"
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#include "error.h"
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static void usage ();
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/* The name under which this program was run. */
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char *program_name;
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/* If nonzero, return an exit status but produce no output. */
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static int silent;
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/* If non-zero, display usage information and exit. */
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static int show_help;
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/* If non-zero, print the version on standard output and exit. */
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static int show_version;
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static struct option const longopts[] =
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{
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{"help", no_argument, &show_help, 1},
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{"silent", no_argument, NULL, 's'},
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{"quiet", no_argument, NULL, 's'},
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{"version", no_argument, &show_version, 1},
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{NULL, 0, NULL, 0}
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};
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void
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main (argc, argv)
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int argc;
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char **argv;
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{
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char *tty;
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int optc;
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program_name = argv[0];
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silent = 0;
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while ((optc = getopt_long (argc, argv, "s", longopts, (int *) 0)) != EOF)
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{
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switch (optc)
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{
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case 0:
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break;
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case 's':
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silent = 1;
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break;
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default:
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usage (2);
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}
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}
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if (show_version)
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{
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printf ("tty - %s\n", version_string);
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exit (0);
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}
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if (show_help)
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usage (0);
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if (optind != argc)
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usage (2);
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tty = ttyname (0);
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if (!silent)
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{
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if (tty)
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puts (tty);
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else
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puts ("not a tty");
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if (ferror (stdout) || fclose (stdout) == EOF)
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error (3, errno, "standard output");
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}
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exit (isatty (0) ? 0 : 1);
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}
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static void
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usage (status)
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int status;
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{
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if (status != 0)
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fprintf (stderr, "Try `%s --help' for more information.\n",
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program_name);
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else
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{
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printf ("Usage: %s [OPTION]...\n", program_name);
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printf ("\
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\n\
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-s, --silent, --quiet print nothing, only return an exit status\n\
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--help display this help and exit\n\
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--version output version information and exit\n\
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");
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}
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exit (status);
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}
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