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Updated: July 2017

visudo (1m)


visudo - edit the sudoers file


visudo [-chqsV] [-f sudoers] [-x output_file]


VISUDO(8)                   System Manager's Manual                  VISUDO(8)

       visudo - edit the sudoers file

       visudo [-chqsV] [-f sudoers] [-x output_file]

       visudo edits the sudoers file in a safe fashion, analogous to vipw(1m).
       visudo locks the sudoers file against multiple simultaneous edits,
       provides basic sanity checks, and checks for parse errors.  If the
       sudoers file is currently being edited you will receive a message to
       try again later.

       There is a hard-coded list of one or more editors that visudo will use
       set at compile-time that may be overridden via the editor sudoers
       Default variable.  This list defaults to vi.  Normally, visudo does not
       honor the VISUAL or EDITOR environment variables unless they contain an
       editor in the aforementioned editors list.  However, if visudo is
       configured with the --with-env-editor option or the env_editor Default
       variable is set in sudoers, visudo will use any the editor defines by
       VISUAL or EDITOR.  Note that this can be a security hole since it
       allows the user to execute any program they wish simply by setting
       VISUAL or EDITOR.

       visudo parses the sudoers file after the edit and will not save the
       changes if there is a syntax error.  Upon finding an error, visudo will
       print a message stating the line number(s) where the error occurred and
       the user will receive the What now?  prompt.  At this point the user
       may enter `e' to re-edit the sudoers file, `x' to exit without saving
       the changes, or `Q' to quit and save changes.  The `Q' option should be
       used with extreme care because if visudo believes there to be a parse
       error, so will sudo and no one will be able to run sudo again until the
       error is fixed.  If `e' is typed to edit the sudoers file after a parse
       error has been detected, the cursor will be placed on the line where
       the error occurred (if the editor supports this feature).

       The options are as follows:

       -c, --check Enable check-only mode.  The existing sudoers file will be
                   checked for syntax errors, owner and mode.  A message will
                   be printed to the standard output describing the status of
                   sudoers unless the -q option was specified.  If the check
                   completes successfully, visudo will exit with a value of 0.
                   If an error is encountered, visudo will exit with a value
                   of 1.

       -f sudoers, --file=sudoers
                   Specify an alternate sudoers file location.  With this
                   option, visudo will edit (or check) the sudoers file of
                   your choice, instead of the default, /etc/sudoers.  The
                   lock file used is the specified sudoers file with .tmp
                   appended to it.  In check-only mode only, the argument to
                   -f may be `-', indicating that sudoers will be read from
                   the standard input.

       -h, --help  Display a short help message to the standard output and

       -q, --quiet Enable quiet mode.  In this mode details about syntax
                   errors are not printed.  This option is only useful when
                   combined with the -c option.

       -s, --strict
                   Enable strict checking of the sudoers file.  If an alias is
                   used before it is defined, visudo will consider this a
                   parse error.  Note that it is not possible to differentiate
                   between an alias and a host name or user name that consists
                   solely of uppercase letters, digits, and the underscore
                   (`_') character.

       -V, --version
                   Print the visudo and sudoers grammar versions and exit.

       -x output_file, --export=output_file
                   Export a sudoers in JSON format and write it to
                   output_file.  If output_file is `-', the exported sudoers
                   policy will be written to the standard output.  By default,
                   /etc/sudoers (and any files it includes) will be exported.
                   The -f option can be used to specify a different sudoers
                   file to export.  The exported format is intended to be
                   easier for third-party applications to parse than the
                   traditional sudoers format.  The various values have
                   explicit types which removes much of the ambiguity of the
                   sudoers format.

   Debugging and sudoers plugin arguments
       visudo versions 1.8.4 and higher support a flexible debugging framework
       that is configured via Debug lines in the sudo.conf(4) file.

       Starting with sudo 1.8.12, visudo will also parse the arguments to the
       sudoers plugin to override the default sudoers path name, UID, GID and
       file mode.  These arguments, if present, should be listed after the
       path to the plugin (i.e. after sudoers.so).  Multiple arguments may be
       specified, separated by white space.  For example:

             Plugin sudoers_policy sudoers.so sudoers_mode=0400

       The following arguments are supported:

                 The sudoers_file argument can be used to override the default
                 path to the sudoers file.

                 The sudoers_uid argument can be used to override the default
                 owner of the sudoers file.  It should be specified as a
                 numeric user ID.

                 The sudoers_gid argument can be used to override the default
                 group of the sudoers file.  It must be specified as a numeric
                 group ID (not a group name).

                 The sudoers_mode argument can be used to override the default
                 file mode for the sudoers file.  It should be specified as an
                 octal value.

       For more information on configuring sudo.conf(4), please refer to its

       The following environment variables may be consulted depending on the
       value of the editor and env_editor sudoers settings:

       VISUAL           Invoked by visudo as the editor to use

       EDITOR           Used by visudo if VISUAL is not set

       /etc/sudo.conf            Sudo front end configuration

       /etc/sudoers              List of who can run what

       /etc/sudoers.tmp          Lock file for visudo

       sudoers file busy, try again later.
             Someone else is currently editing the sudoers file.

       /etc/sudoers.tmp: Permission denied
             You didn't run visudo as root.

       Can't find you in the passwd database
             Your user ID does not appear in the system passwd file.

       Warning: {User,Runas,Host,Cmnd}_Alias referenced but not defined
             Either you are trying to use an undeclared
             {User,Runas,Host,Cmnd}_Alias or you have a user or host name
             listed that consists solely of uppercase letters, digits, and the
             underscore (`_') character.  In the latter case, you can ignore
             the warnings (sudo will not complain) .  In -s (strict) mode
             these are errors, not warnings.

       Warning: unused {User,Runas,Host,Cmnd}_Alias
             The specified {User,Runas,Host,Cmnd}_Alias was defined but never
             used.  You may wish to comment out or remove the unused alias.

       Warning: cycle in {User,Runas,Host,Cmnd}_Alias
             The specified {User,Runas,Host,Cmnd}_Alias includes a reference
             to itself, either directly or through an alias it includes.  This
             is only a warning by default as sudo will ignore cycles when
             parsing the sudoers file.

       visudo: /etc/sudoers: input and output files must be different
             The -x flag was used and the specified output_file has the same
             path name as the sudoers file to export.

       See attributes(5) for descriptions of the following attributes:

       |Availability   | security/sudo    |
       |Stability      | Uncommitted      |
       vi(1), sudo.conf(4), sudoers(4), sudo(1m), vipw(1m)

       Many people have worked on sudo over the years; this version consists
       of code written primarily by:

             Todd C. Miller

       See the CONTRIBUTORS file in the sudo distribution
       (https://www.sudo.ws/contributors.html) for an exhaustive list of
       people who have contributed to sudo.

       There is no easy way to prevent a user from gaining a root shell if the
       editor used by visudo allows shell escapes.

       If you feel you have found a bug in visudo, please submit a bug report
       at https://bugzilla.sudo.ws/

       Limited free support is available via the sudo-users mailing list, see
       https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
       the archives.

       visudo is provided AS IS and any express or implied warranties,
       including, but not limited to, the implied warranties of
       merchantability and fitness for a particular purpose are disclaimed.
       See the LICENSE file distributed with sudo or
       https://www.sudo.ws/license.html for complete details.

       This software was built from source available at
       https://java.net/projects/solaris-userland.  The original community
       source was downloaded from

       Further information about this software can be found on the open source
       community website at http://www.sudo.ws/.

Sudo 1.8.18p1                  November 20, 2015                     VISUDO(8)