2 Copyright (c) 1996,1998-2005, 2007 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.
21 $Sudo: visudo.pod,v 1.38.2.9 2007/08/13 16:23:31 millert Exp $
26 visudo - edit the sudoers file
30 B<visudo> [B<-c>] [B<-q>] [B<-s>] [B<-V>] [B<-f> I<sudoers>]
34 B<visudo> edits the I<sudoers> file in a safe fashion, analogous to
35 L<vipw(8)>. B<visudo> locks the I<sudoers> file against multiple
36 simultaneous edits, provides basic sanity checks, and checks
37 for parse errors. If the I<sudoers> file is currently being
38 edited you will receive a message to try again later.
40 There is a hard-coded list of editors that B<visudo> will use set
41 at compile-time that may be overridden via the I<editor> I<sudoers>
42 C<Default> variable. This list defaults to the path to L<vi(1)> on
43 your system, as determined by the I<configure> script. Normally,
44 B<visudo> does not honor the C<VISUAL> or C<EDITOR> environment
45 variables unless they contain an editor in the aforementioned editors
46 list. However, if B<visudo> is configured with the I<--with-enveditor>
47 flag or the I<env_editor> C<Default> variable is set in I<sudoers>,
48 B<visudo> will use any the editor defines by C<VISUAL> or C<EDITOR>.
49 Note that this can be a security hole since it allows the user to
50 execute any program they wish simply by setting C<VISUAL> or C<EDITOR>.
52 B<visudo> parses the I<sudoers> file after the edit and will
53 not save the changes if there is a syntax error. Upon finding
54 an error, B<visudo> will print a message stating the line number(s)
55 where the error occurred and the user will receive the
56 "What now?" prompt. At this point the user may enter "e"
57 to re-edit the I<sudoers> file, "x" to exit without
58 saving the changes, or "Q" to quit and save changes. The
59 "Q" option should be used with extreme care because if B<visudo>
60 believes there to be a parse error, so will B<sudo> and no one
61 will be able to B<sudo> again until the error is fixed.
62 If "e" is typed to edit the I<sudoers> file after a parse error
63 has been detected, the cursor will be placed on the line where the
64 error occurred (if the editor supports this feature).
68 B<visudo> accepts the following command line options:
74 Enable B<check-only> mode. The existing I<sudoers> file will be
75 checked for syntax and a message will be printed to the
76 standard output detailing the status of I<sudoers>.
77 If the syntax check completes successfully, B<visudo> will
78 exit with a value of 0. If a syntax error is encountered,
79 B<visudo> will exit with a value of 1.
83 Specify and alternate I<sudoers> file location. With this option
84 B<visudo> will edit (or check) the I<sudoers> file of your choice,
85 instead of the default, F<@sysconfdir@/sudoers>. The lock file used
86 is the specified I<sudoers> file with ".tmp" appended to it.
90 Enable B<quiet> mode. In this mode details about syntax errors
91 are not printed. This option is only useful when combined with
96 Enable B<strict> checking of the I<sudoers> file. If an alias is
97 used before it is defined, B<visudo> will consider this a parse
98 error. Note that it is not possible to differentiate between an
99 alias and a hostname or username that consists solely of uppercase
100 letters, digits, and the underscore ('_') character.
104 The B<-V> (version) option causes B<visudo> to print its version number
111 The following environment variables are used only if B<visudo>
112 was configured with the I<--with-env-editor> option:
118 Invoked by visudo as the editor to use
122 Used by visudo if VISUAL is not set
130 =item F<@sysconfdir@/sudoers>C< >List of who can run what
132 =item F<@sysconfdir@/sudoers.tmp>C< >Lock file for visudo
140 =item sudoers file busy, try again later.
142 Someone else is currently editing the I<sudoers> file.
144 =item @sysconfdir@/sudoers.tmp: Permission denied
146 You didn't run B<visudo> as root.
148 =item Can't find you in the passwd database
150 Your userid does not appear in the system passwd file.
152 =item Warning: undeclared Alias referenced near ...
154 Either you are using a {User,Runas,Host,Cmnd}_Alias before
155 defining it or you have a user or hostname listed that
156 consists solely of uppercase letters, digits, and the
157 underscore ('_') character. If the latter, you can ignore
158 the warnings (B<sudo> will not complain). In B<-s> (strict)
159 mode these are errors, not warnings.
161 =item Warning: runas_default set after old value is in use ...
163 You have a I<runas_default> Defaults setting listed in the I<sudoers>
164 file after its value has already been used. This means that entries
165 prior to the I<runas_default> setting will match based on the default
166 value of I<runas_default> (C<@runas_default@>) whereas entries
167 B<after> the I<runas_default> setting will match based on the new
168 value. This is usually unintentional and in most cases the
169 <runas_default> setting should be placed before any C<Runas_Alias>
170 or User specifications. In B<-s> (strict) mode this is an error,
177 L<vi(1)>, L<sudoers(5)>, L<sudo(8)>, L<vipw(8)>
181 Many people have worked on I<sudo> over the years; this version of
182 B<visudo> was written by:
186 See the HISTORY file in the sudo distribution or visit
187 http://www.sudo.ws/sudo/history.html for more details.
191 There is no easy way to prevent a user from gaining a root shell if
192 the editor used by B<visudo> allows shell escapes.
196 If you feel you have found a bug in B<visudo>, please submit a bug report
197 at http://www.sudo.ws/sudo/bugs/
201 Limited free support is available via the sudo-users mailing list,
202 see http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or
207 B<visudo> is provided ``AS IS'' and any express or implied warranties,
208 including, but not limited to, the implied warranties of merchantability
209 and fitness for a particular purpose are disclaimed. See the LICENSE
210 file distributed with B<sudo> or http://www.sudo.ws/sudo/license.html
211 for complete details.