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

NAME
     visudo -- edit the	sudoers	file

SYNOPSIS
     visudo [-cqsV] [-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.  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 /usr/bin/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 config-
     ured 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 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		 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	 Specify and 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.

     -q		 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		 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 (`_') charac-
		 ter.

     -V		 The -V	(version) option causes	visudo to print	its version
		 number	and exit.

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
     /etc/sudoers	       List of who can run what

     /etc/sudoers.tmp	       Lock file for visudo

DIAGNOSTICS
     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 under-
	   score (`_') 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.  In
	   -s (strict) mode this is an error, not a warning.

     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.

SEE ALSO
     vi(1), 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
     (http://www.sudo.ws/sudo/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
     http://www.sudo.ws/sudo/bugs/

SUPPORT
     Limited free support is available via the sudo-users mailing list,	see
     http://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 http://www.sudo.ws/sudo/license.html	for
     complete details.

FreeBSD	9.2			 July 26, 2014			   FreeBSD 9.2

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

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