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       visudo - edit the sudoers file

       visudo [ -c ] [ -f sudoers ] [ -q ] [ -s ] [ -V ]

       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

       There is a hard-coded list of editors that visudo will use set at com
       pile-time that may be overridden via the editor sudoers Default vari
       able.  This list defaults to the path to vi(1) on your system, as
       determined by the configure script.  Normally, visudo does not honor
       the VISUAL or EDITOR environment variables unless they contain an edi
       tor in the aforementioned editors list.	However, if visudo is config
       ured with the --with-enveditor flag or the enveditor 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).

       visudo accepts the following command line options:

       -c  Enable check-only mode.  The existing sudoers file will be checked
	   for syntax and a message will be printed to the standard output
	   detailing the status of sudoers.  If the syntax check completes
	   successfully, visudo will exit with a value of 0.  If a syntax
	   error is encountered, visudo will exit with a value of 1.

       -f  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.

       -q  Enable quiet mode.  In this mode details about syntax errors are
	   not printed.  This option is only useful when combined with the -c

       -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 hostname or username that consists solely of uppercase letters,
	   digits, and the underscore (_) character.

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

       The following environment variables are used only if visudo was config
       ured with the --with-env-editor option:

	VISUAL		       Invoked by visudo as the editor to use
	EDITOR		       Used by visudo if VISUAL is not set

	/etc/sudoers	       List of who can run what
	/etc/sudoers.tmp       Lock file for visudo

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

       /etc/sudoers.tmp: Permission denied
	   You didnt run visudo as root.

       Cant find you in the passwd database
	   Your userid does not appear in the system passwd file.

       Warning: undeclared Alias referenced near ...
	   Either you are using a {User,Runas,Host,Cmnd}_Alias before defining
	   it or you have a user or hostname listed that consists solely of
	   uppercase letters, digits, and the underscore (_) character.  If
	   the latter, you can ignore the warnings (sudo will not complain).
	   In -s (strict) mode these are errors, not warnings.

       Warning: runas_default set after old value is in use ...
	   You have a runas_default Defaults setting listed in the sudoers
	   file after its value has already been used.	This means that
	   entries prior to the runas_default setting will match based on the
	   default value of runas_default (root) whereas entries after the
	   runas_default setting will match based on the new value.  This is
	   usually unintentional and in most cases the  setting
	   should be placed before any Runas_Alias or User specifications.  In
	   -s (strict) mode this is an error, not a warning.

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

       Many people have worked on sudo over the years; this version of visudo
       was written by:

	Todd Miller

       See the HISTORY file in the sudo distribution or visit
       http://www.sudo.ws/sudo/history.html for more details.

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

       If you feel you have found a bug in visudo, please submit a bug report
       at http://www.sudo.ws/sudo/bugs/

       Commercial support is available for sudo, see
       http://www.sudo.ws/sudo/support.html for details.

       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.

       Visudo is provided AS IS and any express or implied warranties,
       including, but not limited to, the implied warranties of merchantabil
       ity 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.

1.6.8p12			 June 20, 2005			     VISUDO(8)

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