Another GNUism that turned out into a meme:
GNU true(1), an utility that is supposed to return zero (true), can return non-zero (false).
That's because it does way more than return 0.
Compare OpenBSD implementation of true(1) with GNU's.
/* Exit with a status code indicating success.
Copyright (C) 1999-2020 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/>. */
void
usage (int status)
{
printf (_("\
Usage: %s [ignored command line arguments]\n\
or: %s OPTION\n\
"),
program_name, program_name);
printf ("%s\n\n",
_(EXIT_STATUS == EXIT_SUCCESS
? N_("Exit with a status code indicating success.")
: N_("Exit with a status code indicating failure.")));
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
emit_ancillary_info (PROGRAM_NAME);
exit (status);
}
int
main (int argc, char **argv)
{
/* Recognize --help or --version only if it's the only command-line
argument. */
if (argc == 2)
{
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
/* Note true(1) will return EXIT_FAILURE in the
edge case where writes fail with GNU specific options. */
atexit (close_stdout);
if (STREQ (argv[1], "--help"))
usage (EXIT_STATUS);
