1VISUDO(8) BSD System Manager's Manual VISUDO(8)
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4 visudo — edit the sudoers file
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7 visudo [-chqsV] [[-f] sudoers]
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10 visudo edits the sudoers file in a safe fashion, analogous to vipw(8).
11 visudo locks the sudoers file against multiple simultaneous edits, per‐
12 forms basic validity checks, and checks for syntax errors before in‐
13 stalling the edited file. If the sudoers file is currently being edited
14 you will receive a message to try again later.
15 visudo parses the sudoers file after editing and will not save the
17 changes if there is a syntax error. Upon finding an error, visudo will
18 print a message stating the line number(s) where the error occurred and
19 the user will receive the “What now?” prompt. At this point the user may
20 enter ‘e’ to re-edit the sudoers file, ‘x’ to exit without saving the
21 changes, or ‘Q’ to quit and save changes. The ‘Q’ option should be used
22 with extreme caution because if visudo believes there to be a syntax er‐
23 ror, so will sudo and no one will be able to run sudo again until the er‐
24 ror is fixed. If ‘e’ is typed to edit the sudoers file after a syntax
25 error has been detected, the cursor will be placed on the line where the
26 error occurred (if the editor supports this feature).
27 There are two sudoers settings that determine which editor visudo will
29 run.
30 editor A colon (‘:’) separated list of editors allowed to be used with
32 visudo. visudo will choose the editor that matches the user's
33 SUDO_EDITOR, VISUAL or EDITOR environment variable if possible,
34 or the first editor in the list that exists and is executable.
35 Note that sudo does not preserve the SUDO_EDITOR, VISUAL or
36 EDITOR environment variables unless they are present in the
37 env_keep list or the env_reset option is disabled in the
38 sudoers file. The default editor path is
39 /usr/bin/nano:/usr/bin/vim:/usr/bin/vi which can be set at com‐
40 pile time via the --with-editor configure option.
41 env_editor
43 If set, visudo will use the value of the SUDO_EDITOR, VISUAL or
44 EDITOR environment variables before falling back on the default
45 editor list. Note that visudo is typically run as root so this
46 option may allow a user with visudo privileges to run arbitrary
47 commands as root without logging. An alternative is to place a
48 colon-separated list of “safe” editors int the editor variable.
49 visudo will then only use SUDO_EDITOR, VISUAL or EDITOR if they
50 match a value specified in editor. If the env_reset flag is
51 enabled, the SUDO_EDITOR, VISUAL and/or EDITOR environment
52 variables must be present in the env_keep list for the
53 env_editor flag to function when visudo is invoked via sudo.
54 The default value is on, which can be set at compile time via
55 the --with-env-editor configure option.
56 The options are as follows:
58 -c, --check
60 Enable check-only mode. The existing sudoers file (and any
61 other files it includes) will be checked for syntax errors.
62 If the path to the sudoers file was not specified, visudo
63 will also check the file owner and mode. A message will be
64 printed to the standard output describing the status of
65 sudoers unless the -q option was specified. If the check
66 completes successfully, visudo will exit with a value of 0.
67 If an error is encountered, visudo will exit with a value of
68 1.
69 -f sudoers, --file=sudoers
71 Specify an alternate sudoers file location, see below. As of
72 version 1.8.27, the sudoers path can be specified without us‐
73 ing the -f option.
74 -h, --help Display a short help message to the standard output and exit.
76 -q, --quiet
78 Enable quiet mode. In this mode details about syntax errors
79 are not printed. This option is only useful when combined
80 with the -c option.
81 -s, --strict
83 Enable strict checking of the sudoers file. If an alias is
84 referenced but not actually defined or if there is a cycle in
85 an alias, visudo will consider this a syntax error. Note
86 that it is not possible to differentiate between an alias and
87 a host name or user name that consists solely of uppercase
88 letters, digits, and the underscore (‘_’) character.
89 -V, --version
91 Print the visudo and sudoers grammar versions and exit.
92 A sudoers file may be specified instead of the default, /etc/sudoers.
94 The temporary file used is the specified sudoers file with “.tmp” ap‐
95 pended to it. In check-only mode only, ‘-’ may be used to indicate that
96 sudoers will be read from the standard input. Because the policy is
97 evaluated in its entirety, it is not sufficient to check an individual
98 sudoers include file for syntax errors.
99 Debugging and sudoers plugin arguments
101 visudo versions 1.8.4 and higher support a flexible debugging framework
102 that is configured via Debug lines in the sudo.conf(5) file.
103 Starting with sudo 1.8.12, visudo will also parse the arguments to the
105 sudoers plugin to override the default sudoers path name, UID, GID and
106 file mode. These arguments, if present, should be listed after the path
107 to the plugin (i.e., after sudoers.so). Multiple arguments may be speci‐
108 fied, separated by white space. For example:
109 Plugin sudoers_policy sudoers.so sudoers_mode=0400
111 The following arguments are supported:
113 sudoers_file=pathname
115 The sudoers_file argument can be used to override the default
116 path to the sudoers file.
117 sudoers_uid=uid
119 The sudoers_uid argument can be used to override the default
120 owner of the sudoers file. It should be specified as a numeric
121 user-ID.
122 sudoers_gid=gid
124 The sudoers_gid argument can be used to override the default
125 group of the sudoers file. It must be specified as a numeric
126 group-ID (not a group name).
127 sudoers_mode=mode
129 The sudoers_mode argument can be used to override the default
130 file mode for the sudoers file. It should be specified as an
131 octal value.
132 For more information on configuring sudo.conf(5), please refer to its
134 manual.
135
137 The following environment variables may be consulted depending on the
138 value of the editor and env_editor sudoers settings:
139 SUDO_EDITOR Invoked by visudo as the editor to use
141 VISUAL Used by visudo if SUDO_EDITOR is not set
143 EDITOR Used by visudo if neither SUDO_EDITOR nor VISUAL is set
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147 /etc/sudo.conf Sudo front end configuration
148 /etc/sudoers List of who can run what
150 /etc/sudoers.tmp Default temporary file used by visudo
152
154 In addition to reporting sudoers syntax errors, visudo may produce the
155 following messages:
156 sudoers file busy, try again later.
158 Someone else is currently editing the sudoers file.
159 /etc/sudoers: Permission denied
161 You didn't run visudo as root.
162 you do not exist in the passwd database
164 Your user-ID does not appear in the system passwd database.
165 Warning: {User,Runas,Host,Cmnd}_Alias referenced but not defined
167 Either you are trying to use an undeclared
168 {User,Runas,Host,Cmnd}_Alias or you have a user or host name listed
169 that consists solely of uppercase letters, digits, and the under‐
170 score (‘_’) character. In the latter case, you can ignore the
171 warnings (sudo will not complain). The message is prefixed with
172 the path name of the sudoers file and the line number where the un‐
173 defined alias was used. In -s (strict) mode these are errors, not
174 warnings.
175 Warning: unused {User,Runas,Host,Cmnd}_Alias
177 The specified {User,Runas,Host,Cmnd}_Alias was defined but never
178 used. The message is prefixed with the path name of the sudoers
179 file and the line number where the unused alias was defined. You
180 may wish to comment out or remove the unused alias.
181 Warning: cycle in {User,Runas,Host,Cmnd}_Alias
183 The specified {User,Runas,Host,Cmnd}_Alias includes a reference to
184 itself, either directly or through an alias it includes. The mes‐
185 sage is prefixed with the path name of the sudoers file and the
186 line number where the cycle was detected. This is only a warning
187 unless visudo is run in -s (strict) mode as sudo will ignore cycles
188 when parsing the sudoers file.
189 unknown defaults entry "name"
191 The sudoers file contains a Defaults setting not recognized by
192 visudo.
193
195 vi(1), sudo.conf(5), sudoers(5), sudo(8), vipw(8)
196
198 Many people have worked on sudo over the years; this version consists of
199 code written primarily by:
200 Todd C. Miller
202 See the CONTRIBUTORS file in the sudo distribution
204 (https://www.sudo.ws/contributors.html) for an exhaustive list of people
205 who have contributed to sudo.
206
208 There is no easy way to prevent a user from gaining a root shell if the
209 editor used by visudo allows shell escapes.
210
212 If you feel you have found a bug in visudo, please submit a bug report at
213 https://bugzilla.sudo.ws/
214
216 Limited free support is available via the sudo-users mailing list, see
217 https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
218 the archives.
219
221 visudo is provided “AS IS” and any express or implied warranties, includ‐
222 ing, but not limited to, the implied warranties of merchantability and
223 fitness for a particular purpose are disclaimed. See the LICENSE file
224 distributed with sudo or https://www.sudo.ws/license.html for complete
225 details.
226Sudo 1.9.8p2 August 27, 2020 Sudo 1.9.8p2