VISUDO(8) | Maintenance Commands and Procedures | VISUDO(8) |
visudo
—
visudo |
[-chOPqsV ] [[-f ]
sudoers] |
visudo
edits the sudoers file in a
safe fashion, analogous to vipw(8).
visudo
locks the sudoers file
against multiple simultaneous edits, performs basic validity checks, and
checks for syntax 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
syntax error, so will sudo
. If
‘e
’ is typed to edit the
sudoers file after a syntax error 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.
:
’) 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. 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
/usr/bin/vi which can be set at compile time via
the --with-editor
configure option.visudo
will use the value of the
SUDO_EDITOR
, VISUAL
, or
EDITOR
environment variables before falling back
on the default editor list. 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 in 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
visudo
will also check the
file ownership and permissions (see the -O
and
-P
options). 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-f
option.-h
,
--help
-O
,
--owner
-c
), an
error will be reported if the owner is incorrect. This option is enabled
by default if the sudoers file was not specified.-P
,
--perms
-c
), an error will be
reported if the file permissions are incorrect. This option is enabled by
default if the sudoers file was not specified.-q
,
--quiet
-c
option.-s
,
--strict
visudo
will consider this a
syntax error. 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
,
--version
visudo
and sudoers
grammar versions and exit.A sudoers file may be specified instead of the
default, /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. Because the
policy is evaluated in its entirety, it is not sufficient to check an
individual sudoers include file for syntax errors.
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, user-ID, group-ID, 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
specified, separated by white space. For example:
Plugin sudoers_policy sudoers.so sudoers_mode=0400
The following arguments are supported:
For more information on configuring sudo.conf(5), refer to its manual.
SUDO_EDITOR
visudo
as the editor to useVISUAL
visudo
if
SUDO_EDITOR
is not setEDITOR
visudo
if neither
SUDO_EDITOR
nor VISUAL
is
setvisudo
may produce the following messages:
sudoers
file busy, try again later.
/etc/sudoers:
Permission denied
visudo
as root.you
do not exist in the passwd database
Warning:
{User,Runas,Host,Cmnd}_Alias referenced but not defined
_
’) 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 undefined
alias was used. In -s
(strict) mode these are
errors, not warnings.Warning:
unused {User,Runas,Host,Cmnd}_Alias
Warning:
cycle in {User,Runas,Host,Cmnd}_Alias
visudo
is run in -s
(strict) mode as sudo
will ignore cycles when
parsing the sudoers file.unknown
defaults entry "name"
Defaults
setting not recognized by
visudo
.sudo
over the years; this
version consists of code written primarily by:
See the CONTRIBUTORS.md file in the sudo
distribution (https://www.sudo.ws/about/contributors/) for an exhaustive
list of people who have contributed to sudo
.
visudo
allows shell escapes.
visudo
, you can
submit a bug report at https://bugzilla.sudo.ws/
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.md file distributed with sudo
or
https://www.sudo.ws/about/license/ for complete details.
April 23, 2022 | Sudo 1.9.11p3 |