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


NAME

     visudo - edit the sudoers file


SYNOPSIS

     visudo [-chOPqsV] [[-f] sudoers]


DESCRIPTION

     visudo edits the sudoers file in a safe fashion, analogous to vipw(8).
     visudo locks the sudoers file against multiple simultaneous edits, performs
     basic validity checks, and checks for syntax errors before installing the
     edited file.  If the sudoers file is currently being edited you will
     receive a message to try again later.

     visudo parses the sudoers file after editing 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
     caution because if visudo believes there to be a syntax error, so will
     sudo.  If `e' is typed to edit the sudoers file after a syntax error has
     been detected, the cursor will be placed on the line where the error
     occurred (if the editor supports this feature).

     There are two sudoers settings that determine which editor visudo will run.

     editor    A colon (`:') separated list of editors allowed to be used with
               visudo.  visudo will choose the editor that matches the user's
               SUDO_EDITOR, VISUAL, or EDITOR environment variable if possible,
               or the first editor in the list that exists and is executable.
               sudo does not preserve the SUDO_EDITOR, VISUAL, or EDITOR
               environment variables unless they are present in the env_keep
               list or the env_reset option is disabled in the sudoers file.
               The default editor path is /usr/bin/vi which can be set at
               compile time via the --with-editor configure option.

     env_editor
               If set, visudo will use the value of the SUDO_EDITOR, VISUAL, or
               EDITOR environment variables before falling back on the default
               editor list.  visudo is typically run as root so this option may
               allow a user with visudo privileges to run arbitrary commands as
               root without logging.  An alternative is to place a colon-
               separated list of "safe" editors in the editor variable.  visudo
               will then only use SUDO_EDITOR, VISUAL, or EDITOR if they match a
               value specified in editor.  If the env_reset flag is enabled, the
               SUDO_EDITOR, VISUAL, and/or EDITOR environment variables must be
               present in the env_keep list for the env_editor flag to function
               when visudo is invoked via sudo.  The default value is on, which
               can be set at compile time via the --with-env-editor configure
               option.

     The options are as follows:

     -c, --check
                 Enable check-only mode.  The existing sudoers file (and any
                 other files it includes) will be checked for syntax errors.  If
                 the path to the sudoers file was not specified, visudo will
                 also check the file ownership and permissions (see the -O and
                 -P options).  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, see below.  As of
                 version 1.8.27, the sudoers path can be specified without using
                 the -f option.

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

     -O, --owner
                 Enforce the default ownership (user and group) of the sudoers
                 file.  In edit mode, the owner of the edited file will be set
                 to the default.  In check mode (-c), an error will be reported
                 if the owner is incorrect.  This option is enabled by default
                 if the sudoers file was not specified.

     -P, --perms
                 Enforce the default permissions (mode) of the sudoers file.  In
                 edit mode, the permissions of the edited file will be set to
                 the default.  In check mode (-c), an error will be reported if
                 the file permissions are incorrect.  This option is enabled by
                 default if the sudoers file was not specified.

     -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
                 referenced but not actually defined or if there is a cycle in
                 an alias, visudo will consider this a syntax error.  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.

     A sudoers file may be specified instead of the default,
     /opt/local/etc/sudoers.  The temporary file used is the specified sudoers
     file with ".tmp" appended to it.  In check-only mode only, `-' may be used
     to indicate that sudoers will be read from the standard input.  Because the
     policy is evaluated in its entirety, it is not sufficient to check an
     individual sudoers include file for syntax errors.

   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(5) file.

     Starting with sudo 1.8.12, visudo will also parse the arguments to the
     sudoers plugin to override the default sudoers path name, user-ID, group-
     ID, 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:

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

     sudoers_uid=user-ID
               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.

     sudoers_gid=group-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).

     sudoers_mode=mode
               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(5), refer to its manual.


ENVIRONMENT

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

     SUDO_EDITOR      Invoked by visudo as the editor to use

     VISUAL           Used by visudo if SUDO_EDITOR is not set

     EDITOR           Used by visudo if neither SUDO_EDITOR nor VISUAL is set


FILES

     /opt/local/etc/sudo.conf  Sudo front-end configuration

     /opt/local/etc/sudoers    List of who can run what

     /opt/local/etc/sudoers.tmp
                               Default temporary file used by visudo


DIAGNOSTICS

     In addition to reporting sudoers syntax errors, visudo may produce the
     following messages:

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

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

     you do not exist in the passwd database
           Your user-ID does not appear in the system passwd database.

     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).  The message is prefixed with the path name
           of the sudoers file and the line number where the undefined alias was
           used.  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.  The message is prefixed with the path name of the sudoers file
           and the line number where the unused alias was defined.  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.  The message
           is prefixed with the path name of the sudoers file and the line
           number where the cycle was detected.  This is only a warning unless
           visudo is run in -s (strict) mode as sudo will ignore cycles when
           parsing the sudoers file.

     unknown defaults entry "name"
           The sudoers file contains a Defaults setting not recognized by
           visudo.


SEE ALSO

     vi(1), sudo.conf(5), sudoers(5), sudo(8), vipw(8)


AUTHORS

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

           Todd C. Miller

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


CAVEATS

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


BUGS

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


SUPPORT

     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.


DISCLAIMER

     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.md
     file distributed with sudo or https://www.sudo.ws/about/license/ for
     complete details.

Sudo 1.9.11                      April 23, 2022                      Sudo 1.9.11

sudo 1.9.11 - Generated Tue Jun 7 08:22:41 CDT 2022
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