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/* tty -- print the name of the terminal connected to standard input
Copyright (C) 1990-2021 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 3 of the License, 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, see <https://www.gnu.org/licenses/>. */
/* 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 a tty, 2 if usage error,
3 if write error.
Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
#include <config.h>
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#include "system.h"
#include "error.h"
#include "quote.h"
/* Exit statuses. */
enum
{
TTY_STDIN_NOTTY = 1,
TTY_FAILURE = 2,
TTY_WRITE_ERROR = 3
};
/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "tty"
#define AUTHORS proper_name ("David MacKenzie")
/* If true, return an exit status but produce no output. */
static bool silent;
static struct option const longopts[] =
{
{"silent", no_argument, NULL, 's'},
{"quiet", no_argument, NULL, 's'},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
void
usage (int status)
{
if (status != EXIT_SUCCESS)
emit_try_help ();
else
{
printf (_("Usage: %s [OPTION]...\n"), program_name);
fputs (_("\
Print the file name of the terminal connected to standard input.\n\
\n\
-s, --silent, --quiet print nothing, only return an exit status\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
emit_ancillary_info (PROGRAM_NAME);
}
exit (status);
}
int
main (int argc, char **argv)
{
int optc;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
initialize_exit_failure (TTY_WRITE_ERROR);
atexit (close_stdout);
silent = false;
while ((optc = getopt_long (argc, argv, "s", longopts, NULL)) != -1)
{
switch (optc)
{
case 's':
silent = true;
break;
case_GETOPT_HELP_CHAR;
case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
default:
usage (TTY_FAILURE);
}
}
if (optind < argc)
{
error (0, 0, _("extra operand %s"), quote (argv[optind]));
usage (TTY_FAILURE);
}
errno = ENOENT;
if (silent)
return isatty (STDIN_FILENO) ? EXIT_SUCCESS : TTY_STDIN_NOTTY;
int status = EXIT_SUCCESS;
char const *tty = ttyname (STDIN_FILENO);
if (! tty)
{
tty = _("not a tty");
status = TTY_STDIN_NOTTY;
}
puts (tty);
return status;
}
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