1 /* tty -- print the name of the terminal connected to standard input
2 Copyright (C) 1990-2005, 2008-2012 Free Software Foundation, Inc.
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 3 of the License, or
7 (at your option) any later version.
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.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Displays "not a tty" if stdin is not a terminal.
18 Displays nothing if -s option is given.
19 Exit status 0 if stdin is a tty, 1 if not, 2 if usage error,
22 Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
27 #include <sys/types.h>
40 /* The official name of this program (e.g., no 'g' prefix). */
41 #define PROGRAM_NAME "tty"
43 #define AUTHORS proper_name ("David MacKenzie")
45 /* If true, return an exit status but produce no output. */
48 static struct option
const longopts
[] =
50 {"silent", no_argument
, NULL
, 's'},
51 {"quiet", no_argument
, NULL
, 's'},
52 {GETOPT_HELP_OPTION_DECL
},
53 {GETOPT_VERSION_OPTION_DECL
},
60 if (status
!= EXIT_SUCCESS
)
64 printf (_("Usage: %s [OPTION]...\n"), program_name
);
66 Print the file name of the terminal connected to standard input.\n\
68 -s, --silent, --quiet print nothing, only return an exit status\n\
70 fputs (HELP_OPTION_DESCRIPTION
, stdout
);
71 fputs (VERSION_OPTION_DESCRIPTION
, stdout
);
72 emit_ancillary_info ();
78 main (int argc
, char **argv
)
83 initialize_main (&argc
, &argv
);
84 set_program_name (argv
[0]);
85 setlocale (LC_ALL
, "");
86 bindtextdomain (PACKAGE
, LOCALEDIR
);
89 initialize_exit_failure (TTY_WRITE_ERROR
);
90 atexit (close_stdout
);
94 while ((optc
= getopt_long (argc
, argv
, "s", longopts
, NULL
)) != -1)
102 case_GETOPT_HELP_CHAR
;
104 case_GETOPT_VERSION_CHAR (PROGRAM_NAME
, AUTHORS
);
112 error (0, 0, _("extra operand %s"), quote (argv
[optind
]));
114 tty
= ttyname (STDIN_FILENO
);
120 puts (_("not a tty"));
123 exit (isatty (STDIN_FILENO
) ? EXIT_SUCCESS
: EXIT_FAILURE
);