Manual Pages for UNIX Operating System command usage for man visudo

MAINTENANCE COMMANDS                                   VISUDO(1m)



NAME
     visudo - edit the sudoers file

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

DESCRIPTION
     visudo edits the sudoers file in a safe fashion, analogous
     to vipw(1m).  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 "/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 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 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).

OPTIONS
     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 sudoers  Specify and alternate sudoers file location.



1.7.4              Last change: July 14, 2010                   1






MAINTENANCE COMMANDS                                   VISUDO(1m)



                 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 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 ('_') character.

     -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
     variables:

     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 userid 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 undeclare
         {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



1.7.4              Last change: July 14, 2010                   2






MAINTENANCE COMMANDS                                   VISUDO(1m)



         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.

SEE ALSO
     vi(1), sudoers(4), sudo(1m), vipw(8)

AUTHOR
     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.

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.

ATTRIBUTES
     See attributes(5) for descriptions of the following
     attributes:











1.7.4              Last change: July 14, 2010                   3






MAINTENANCE COMMANDS                                   VISUDO(1m)



     _______________________________________
    |   ATTRIBUTE TYPE   |  ATTRIBUTE VALUE|
    |____________________|__________________|_
    | Availability       |  security/sudo  |
    |____________________|__________________|_
    | Interface Stability|  Uncommitted    |
    |____________________|_________________|

NOTES
     sudo does not create audit(2) records; for a Role Based
     administration solution that performs auditing of all
     actions, please refer to rbac(5).

     Source for sudo is available on http://opensolaris.org.









































1.7.4              Last change: July 14, 2010                   4