1VISUDO(8) MAINTENANCE COMMANDS VISUDO(8)
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6 visudo - edit the sudoers file
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9 visudo [ -c ] [ -f sudoers ] [ -q ] [ -s ] [ -V ]
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12 visudo edits the sudoers file in a safe fashion, analogous to vipw(8).
13 visudo locks the sudoers file against multiple simultaneous edits, pro‐
14 vides basic sanity checks, and checks for parse errors. If the sudoers
15 file is currently being edited you will receive a message to try again
16 later.
17 There is a hard-coded list of editors that visudo will use set at com‐
19 pile-time that may be overridden via the editor sudoers Default vari‐
20 able. This list defaults to the path to vi(1) on your system, as
21 determined by the configure script. Normally, visudo does not honor
22 the VISUAL or EDITOR environment variables unless they contain an edi‐
23 tor in the aforementioned editors list. However, if visudo is config‐
24 ured with the --with-enveditor flag or the enveditor Default variable
25 is set in sudoers, visudo will use any the editor defines by VISUAL or
26 EDITOR. Note that this can be a security hole since it allows the user
27 to execute any program they wish simply by setting VISUAL or EDITOR.
28 visudo parses the sudoers file after the edit and will not save the
30 changes if there is a syntax error. Upon finding an error, visudo will
31 print a message stating the line number(s) where the error occurred and
32 the user will receive the "What now?" prompt. At this point the user
33 may enter "e" to re-edit the sudoers file, "x" to exit without saving
34 the changes, or "Q" to quit and save changes. The "Q" option should be
35 used with extreme care because if visudo believes there to be a parse
36 error, so will sudo and no one will be able to sudo again until the
37 error is fixed. If "e" is typed to edit the sudoers file after a
38 parse error has been detected, the cursor will be placed on the line
39 where the error occurred (if the editor supports this feature).
40
42 visudo accepts the following command line options:
43 -c Enable check-only mode. The existing sudoers file will be checked
45 for syntax and a message will be printed to the standard output
46 detailing the status of sudoers. If the syntax check completes
47 successfully, visudo will exit with a value of 0. If a syntax
48 error is encountered, visudo will exit with a value of 1.
49 -f Specify and alternate sudoers file location. With this option
51 visudo will edit (or check) the sudoers file of your choice,
52 instead of the default, /etc/sudoers. The lock file used is the
53 specified sudoers file with ".tmp" appended to it.
54 -q Enable quiet mode. In this mode details about syntax errors are
56 not printed. This option is only useful when combined with the -c
57 flag.
58 -s Enable strict checking of the sudoers file. If an alias is used
60 before it is defined, visudo will consider this a parse error.
61 Note that it is not possible to differentiate between an alias and
62 a hostname or username that consists solely of uppercase letters,
63 digits, and the underscore ('_') character.
64 -V The -V (version) option causes visudo to print its version number
66 and exit.
67
69 The following environment variables are used only if visudo was config‐
70 ured with the --with-env-editor option:
71 VISUAL Invoked by visudo as the editor to use
73 EDITOR Used by visudo if VISUAL is not set
74
76 /etc/sudoers List of who can run what
77 /etc/sudoers.tmp Lock file for visudo
78
80 sudoers file busy, try again later.
81 Someone else is currently editing the sudoers file.
82 /etc/sudoers.tmp: Permission denied
84 You didn't run visudo as root.
85 Can't find you in the passwd database
87 Your userid does not appear in the system passwd file.
88 Warning: undeclared Alias referenced near ...
90 Either you are using a {User,Runas,Host,Cmnd}_Alias before defining
91 it or you have a user or hostname listed that consists solely of
92 uppercase letters, digits, and the underscore ('_') character. If
93 the latter, you can ignore the warnings (sudo will not complain).
94 In -s (strict) mode these are errors, not warnings.
95 Warning: runas_default set after old value is in use ...
97 You have a runas_default Defaults setting listed in the sudoers
98 file after its value has already been used. This means that
99 entries prior to the runas_default setting will match based on the
100 default value of runas_default (root) whereas entries after the
101 runas_default setting will match based on the new value. This is
102 usually unintentional and in most cases the <runas_default> setting
103 should be placed before any Runas_Alias or User specifications. In
104 -s (strict) mode this is an error, not a warning.
105
107 vi(1), sudoers(5), sudo(8), vipw(8)
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110 Many people have worked on sudo over the years; this version of visudo
111 was written by:
112 Todd Miller
114 See the HISTORY file in the sudo distribution or visit
116 http://www.sudo.ws/sudo/history.html for more details.
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119 There is no easy way to prevent a user from gaining a root shell if the
120 editor used by visudo allows shell escapes.
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123 If you feel you have found a bug in visudo, please submit a bug report
124 at http://www.sudo.ws/sudo/bugs/
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127 Commercial support is available for sudo, see
128 http://www.sudo.ws/sudo/support.html for details.
129 Limited free support is available via the sudo-users mailing list, see
131 http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
132 the archives.
133
135 Visudo is provided ``AS IS'' and any express or implied warranties,
136 including, but not limited to, the implied warranties of merchantabil‐
137 ity and fitness for a particular purpose are disclaimed. See the
138 LICENSE file distributed with sudo or
139 http://www.sudo.ws/sudo/license.html for complete details.
1401.6.8p12 June 20, 2005 VISUDO(8)