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

NAME
     visudo -- edit the	sudoers	file

SYNOPSIS
     visudo [-chqsV] [[-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,	pro-
     vides basic sanity	checks,	and checks for parse 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 parse er-
     ror, so will sudo and no one will be able to run sudo again until the er-
     ror is fixed.  If `e' is typed to edit the	sudoers	file after a parse er-
     ror 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.
	       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 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 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, see below.	 As of
		 version 1.8.27, the sudoers path can be specified without us-
		 ing the -f option.

     -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
		 referenced but	not actually defined or	if there is a cycle in
		 an alias, 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 let-
		 ters, 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,
     /usr/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.  Be-
     cause 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, 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	speci-
     fied, 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:

     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
     /usr/local/etc/sudo.conf  Sudo front end configuration

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

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

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

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

     /usr/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 un-
	   defined 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, includ-
     ing, 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 1.9.2		       October 20, 2019			    Sudo 1.9.2

NAME | SYNOPSIS | DESCRIPTION | ENVIRONMENT | FILES | DIAGNOSTICS | SEE ALSO | AUTHORS | CAVEATS | BUGS | SUPPORT | DISCLAIMER

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