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

NAME

       visudo - edit the sudoers file

SYNOPSIS

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

DESCRIPTION

       visudo edits the sudoers file in a safe fashion, analogous to vipw(8).  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, /private/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 exit.

       -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, /private/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(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, 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:

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

       sudoers_uid=uid
		 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=gid
		 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:

       VISUAL		Invoked by visudo as the editor to use

       EDITOR		Used by visudo if VISUAL is not set

FILES

       /private/etc/sudo.conf	 Sudo front end configuration

       /private/etc/sudoers	 List of who can run what

       /private/etc/sudoers.tmp  Lock file for visudo

DIAGNOSTICS

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

       /private/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: /private/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 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
       complete details.

Sudo 1.8.17p1							 November 20, 2015							 VISUDO(8)