1 Copyright (c) 1996,1998-2005, 2007-2011
2 Todd C. Miller <Todd.Miller@courtesan.com>
4 Permission to use, copy, modify, and distribute this software for any
5 purpose with or without fee is hereby granted, provided that the above
6 copyright notice and this permission notice appear in all copies.
8 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
17 Sponsored in part by the Defense Advanced Research Projects
18 Agency (DARPA) and Air Force Research Laboratory, Air Force
19 Materiel Command, USAF, under agreement number F39502-99-1-0512.
25 visudo - edit the sudoers file
29 B<visudo> [B<-chqsV>] [B<-f> I<sudoers>]
33 B<visudo> edits the I<sudoers> file in a safe fashion, analogous to
34 L<vipw(8)>. B<visudo> locks the I<sudoers> file against multiple
35 simultaneous edits, provides basic sanity checks, and checks
36 for parse errors. If the I<sudoers> file is currently being
37 edited you will receive a message to try again later.
39 There is a hard-coded list of one or more editors that B<visudo> will
40 use set at compile-time that may be overridden via the I<editor> I<sudoers>
41 C<Default> variable. This list defaults to C<"@editor@">. Normally,
42 B<visudo> does not honor the C<VISUAL> or C<EDITOR> environment
43 variables unless they contain an editor in the aforementioned editors
44 list. However, if B<visudo> is configured with the I<--with-env-editor>
45 option or the I<env_editor> C<Default> variable is set in I<sudoers>,
46 B<visudo> will use any the editor defines by C<VISUAL> or C<EDITOR>.
47 Note that this can be a security hole since it allows the user to
48 execute any program they wish simply by setting C<VISUAL> or C<EDITOR>.
50 B<visudo> parses the I<sudoers> file after the edit and will
51 not save the changes if there is a syntax error. Upon finding
52 an error, B<visudo> will print a message stating the line number(s)
53 where the error occurred and the user will receive the
54 "What now?" prompt. At this point the user may enter "e"
55 to re-edit the I<sudoers> file, "x" to exit without
56 saving the changes, or "Q" to quit and save changes. The
57 "Q" option should be used with extreme care because if B<visudo>
58 believes there to be a parse error, so will B<sudo> and no one
59 will be able to B<sudo> again until the error is fixed.
60 If "e" is typed to edit the I<sudoers> file after a parse error
61 has been detected, the cursor will be placed on the line where the
62 error occurred (if the editor supports this feature).
66 B<visudo> accepts the following command line options:
72 Enable B<check-only> mode. The existing I<sudoers> file will be
73 checked for syntax and a message will be printed to the
74 standard output detailing the status of I<sudoers>.
75 If the syntax check completes successfully, B<visudo> will
76 exit with a value of 0. If a syntax error is encountered,
77 B<visudo> will exit with a value of 1.
81 Specify and alternate I<sudoers> file location. With this option
82 B<visudo> will edit (or check) the I<sudoers> file of your choice,
83 instead of the default, F<@sysconfdir@/sudoers>. The lock file used
84 is the specified I<sudoers> file with ".tmp" appended to it.
85 In B<check-only> mode only, the argument to B<-f> may be "-",
86 indicating that I<sudoers> will be read from the standard input.
90 The B<-h> (I<help>) option causes B<visudo> to print a short help message
91 to the standard output and exit.
95 Enable B<quiet> mode. In this mode details about syntax errors
96 are not printed. This option is only useful when combined with
101 Enable B<strict> checking of the I<sudoers> file. If an alias is
102 used before it is defined, B<visudo> will consider this a parse
103 error. Note that it is not possible to differentiate between an
104 alias and a host name or user name that consists solely of uppercase
105 letters, digits, and the underscore ('_') character.
109 The B<-V> (version) option causes B<visudo> to print its version number
116 The following environment variables may be consulted depending on
117 the value of the I<editor> and I<env_editor> I<sudoers> variables:
123 Invoked by visudo as the editor to use
127 Used by visudo if VISUAL is not set
135 =item F<@sysconfdir@/sudoers>
137 List of who can run what
139 =item F<@sysconfdir@/sudoers.tmp>
149 =item sudoers file busy, try again later.
151 Someone else is currently editing the I<sudoers> file.
153 =item @sysconfdir@/sudoers.tmp: Permission denied
155 You didn't run B<visudo> as root.
157 =item Can't find you in the passwd database
159 Your userid does not appear in the system passwd file.
161 =item Warning: {User,Runas,Host,Cmnd}_Alias referenced but not defined
163 Either you are trying to use an undeclare {User,Runas,Host,Cmnd}_Alias
164 or you have a user or host name listed that consists solely of
165 uppercase letters, digits, and the underscore ('_') character. In
166 the latter case, you can ignore the warnings (B<sudo> will not
167 complain). In B<-s> (strict) mode these are errors, not warnings.
169 =item Warning: unused {User,Runas,Host,Cmnd}_Alias
171 The specified {User,Runas,Host,Cmnd}_Alias was defined but never
172 used. You may wish to comment out or remove the unused alias. In
173 B<-s> (strict) mode this is an error, not a warning.
175 =item Warning: cycle in {User,Runas,Host,Cmnd}_Alias
177 The specified {User,Runas,Host,Cmnd}_Alias includes a reference to
178 itself, either directly or through an alias it includes. This is
179 only a warning by default as B<sudo> will ignore cycles when parsing
186 L<vi(1)>, L<sudoers(5)>, L<sudo(8)>, L<vipw(8)>
190 Many people have worked on I<sudo> over the years; this version of
191 B<visudo> was written by:
195 See the HISTORY file in the sudo distribution or visit
196 http://www.sudo.ws/sudo/history.html for more details.
200 There is no easy way to prevent a user from gaining a root shell if
201 the editor used by B<visudo> allows shell escapes.
205 If you feel you have found a bug in B<visudo>, please submit a bug report
206 at http://www.sudo.ws/sudo/bugs/
210 Limited free support is available via the sudo-users mailing list,
211 see http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or
216 B<visudo> is provided ``AS IS'' and any express or implied warranties,
217 including, but not limited to, the implied warranties of merchantability
218 and fitness for a particular purpose are disclaimed. See the LICENSE
219 file distributed with B<sudo> or http://www.sudo.ws/sudo/license.html
220 for complete details.