=cut
Copyright (c) 1996,1998-1999 Todd C. Miller <Todd.Miller@courtesan.com>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
derived from this software without specific prior written permission
from the author.
4. Products derived from this software may not be called "Sudo" nor
may "Sudo" appear in their names without specific prior written
permission from the author.
THIS SOFTWARE 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. IN NO EVENT SHALL
THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
$Sudo: visudo.pod,v 1.20 2000/03/27 03:26:24 millert Exp $
=pod
=head1 NAME
visudo - edit the sudoers file
=head1 SYNOPSIS
B<visudo> [ B<-s> ] [ B<-V> ]
=head1 DESCRIPTION
B<visudo> edits the I<sudoers> file in a safe fashion, analogous to
vipw(@mansectsu@). B<visudo> locks the I<sudoers> file against multiple
simultaneous edits, provides basic sanity checks, and checks
for parse errors. If the I<sudoers> file is currently being
edited you will receive a message to try again later. In the
default configuration, the vi(1) editor is used, but there is
a compile time option to allow use of whatever editor the
environment variables C<EDITOR> or C<VISUAL> are set to.
B<visudo> parses the I<sudoers> file after the edit and will
not save the changes if there is a syntax error. Upon finding
an error, a message will be printed stating the line number(s)
that the error occurred on and the user will receive the
"What now?" prompt. At this point the user may enter "e"
to re-edit the I<sudoers> file, enter "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 B<visudo>
believes there to be a parse error, so will B<sudo> and no one
will be able to execute B<sudo> again until the error is fixed.
Any other command at this prompt will print a short help message.
When editing the I<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).
=head1 OPTIONS
B<visudo> accepts the following command line option:
=over 4
=item -s
Enable B<strict> checking of the I<sudoers> file. If an alias is
used before it is defined, B<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 upper case
letters, digits, and the underscore ('_') character.
=item -V
The C<-V> (version) option causes B<visudo> to print the version number
and exit.
=back
=head1 ERRORS
=over 4
=item sudoers file busy, try again later.
Someone else is currently editing the I<sudoers> file.
=item @sysconfdir@/sudoers.tmp: Permission denied
You didn't run B<visudo> as root.
=item Can't find you in the passwd database
Your userid does not appear in the system passwd file.
=item 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 upper case letters, digits, and the
underscore ('_') character. If the latter, you can ignore
the warnings (B<sudo> will not complain). In B<-s> (strict)
mode these are errors not warnings.
=back
=head1 ENVIRONMENT
The following environment variables are used only if B<visudo>
was configured with the I<--with-env-editor> option:
EDITOR Used by visudo as the editor to use
VISUAL Used by visudo if EDITOR is not set
=head1 FILES
@sysconfdir@/sudoers List of who can run what
@sysconfdir@/sudoers.tmp Lock file for visudo
=head1 AUTHOR
Many people have worked on I<sudo> over the years, this version of
B<visudo> was written by:
Todd Miller <Todd.Miller@courtesan.com>
See the HISTORY file in the sudo distribution for more details.
=head1 BUGS
If you feel you have found a bug in sudo, please submit a bug report
at http://www.courtesan.com/sudo/bugs/
=head1 DISCLAIMER
B<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 B<sudo> for complete details.
=head1 CAVEATS
There is no easy way to prevent a user from gaining a root shell if
the editor used by B<visudo> allows shell escapes.
=head1 SEE ALSO
sudo(@mansectsu@), vipw(@mansectsu@).