1 /* env - run a program in a modified environment
2 Copyright (C) 1986-2015 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 /* Richard Mlynarik and David MacKenzie */
21 #include <sys/types.h>
28 /* The official name of this program (e.g., no 'g' prefix). */
29 #define PROGRAM_NAME "env"
32 proper_name ("Richard Mlynarik"), \
33 proper_name ("David MacKenzie")
35 static struct option
const longopts
[] =
37 {"ignore-environment", no_argument
, NULL
, 'i'},
38 {"null", no_argument
, NULL
, '0'},
39 {"unset", required_argument
, NULL
, 'u'},
40 {GETOPT_HELP_OPTION_DECL
},
41 {GETOPT_VERSION_OPTION_DECL
},
48 if (status
!= EXIT_SUCCESS
)
53 Usage: %s [OPTION]... [-] [NAME=VALUE]... [COMMAND [ARG]...]\n"),
56 Set each NAME to VALUE in the environment and run COMMAND.\n\
59 emit_mandatory_arg_note ();
62 -i, --ignore-environment start with an empty environment\n\
63 -0, --null end each output line with NUL, not newline\n\
64 -u, --unset=NAME remove variable from the environment\n\
66 fputs (HELP_OPTION_DESCRIPTION
, stdout
);
67 fputs (VERSION_OPTION_DESCRIPTION
, stdout
);
70 A mere - implies -i. If no COMMAND, print the resulting environment.\n\
72 emit_ancillary_info (PROGRAM_NAME
);
78 main (int argc
, char **argv
)
81 bool ignore_environment
= false;
82 bool opt_nul_terminate_output
= false;
84 initialize_main (&argc
, &argv
);
85 set_program_name (argv
[0]);
86 setlocale (LC_ALL
, "");
87 bindtextdomain (PACKAGE
, LOCALEDIR
);
90 initialize_exit_failure (EXIT_CANCELED
);
91 atexit (close_stdout
);
93 while ((optc
= getopt_long (argc
, argv
, "+iu:0", longopts
, NULL
)) != -1)
98 ignore_environment
= true;
103 opt_nul_terminate_output
= true;
105 case_GETOPT_HELP_CHAR
;
106 case_GETOPT_VERSION_CHAR (PROGRAM_NAME
, AUTHORS
);
108 usage (EXIT_CANCELED
);
112 if (optind
< argc
&& STREQ (argv
[optind
], "-"))
113 ignore_environment
= true;
115 if (ignore_environment
)
117 static char *dummy_environ
[] = { NULL
};
118 environ
= dummy_environ
;
121 optind
= 0; /* Force GNU getopt to re-initialize. */
122 while ((optc
= getopt_long (argc
, argv
, "+iu:0", longopts
, NULL
)) != -1)
123 if (optc
== 'u' && unsetenv (optarg
))
124 error (EXIT_CANCELED
, errno
, _("cannot unset %s"), quote (optarg
));
126 if (optind
< argc
&& STREQ (argv
[optind
], "-"))
130 while (optind
< argc
&& (eq
= strchr (argv
[optind
], '=')))
132 if (putenv (argv
[optind
]))
135 error (EXIT_CANCELED
, errno
, _("cannot set %s"),
136 quote (argv
[optind
]));
141 /* If no program is specified, print the environment and exit. */
144 char *const *e
= environ
;
146 printf ("%s%c", *e
++, opt_nul_terminate_output
? '\0' : '\n');
150 if (opt_nul_terminate_output
)
152 error (0, errno
, _("cannot specify --null (-0) with command"));
153 usage (EXIT_CANCELED
);
156 execvp (argv
[optind
], &argv
[optind
]);
158 int exit_status
= errno
== ENOENT
? EXIT_ENOENT
: EXIT_CANNOT_INVOKE
;
159 error (0, errno
, "%s", quote (argv
[optind
]));