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visudo(8)                 BSD 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, per-
     forms 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 possi-
               ble, or the first editor in the list that exists and is exe-
               cutable.  Note that 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.  Note that 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 int 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 stan-
                 dard 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 encoun-
                 tered, 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.  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.

     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), please 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 under-
           score (`_') 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 mes-
           sage 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 file in the sudo distribution
     (https://www.sudo.ws/contributors.html) 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 feel you have found a bug in visudo, please 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
     file distributed with sudo or https://www.sudo.ws/license.html for com-
     plete details.

Sudo 1.9.9                     January 20, 2022                     Sudo 1.9.9

sudo 1.9.9 - Generated Sat Jan 29 09:31:36 CST 2022
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