visudo
—
visudo |
[-chqsV -f
sudoers-x
output_file |
visudo
edits the
sudoers file in a safe fashion, analogous to
vipw(8).
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.
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 parse error, so will sudo
and no one
will be able to run 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).
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.
Note that the SUDO_EDITOR
,
VISUAL
and
EDITOR
environment variables are not
preserved by default when the env_reset
sudoers option is enabled. The default editor
path is 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. Note that this may create a
security hole as it allows the user to run any arbitrary command as root
without logging. A safer alternative is to place a colon-separated list of
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
off, which can be set at compile time via the
--with-env-editor
configure option.-c
,
--check
-f
option has not been specified,
visudo
will also check the
sudoers file 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,
--file
=sudoersvisudo
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.
Because the policy is evaluated in its entirety, it is not sufficient to
check an individual sudoers include file for
syntax errors.-h
,
--help
-q
,
--quiet
-c
option.-s
,
--strict
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
,
--version
visudo
and
sudoers grammar versions and exit.-x
output_file,
--export
=output_file-
’, the exported
sudoers policy will be written to the
standard output. By default,
/etc/sudoers (and any files it
includes) will be exported. The -f
option can be used to specify a different
sudoers file to export. The exported format
is intended to be easier for third-party applications to parse than the
traditional sudoers format. The various
values have explicit types which removes much of the ambiguity of the
sudoers format.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, UID, GID 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
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.tmp:
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
./etc/sudoers:
input and output files must be different
-x
flag was used and the specified
output_file has the same path name as the
sudoers file to export.sudo
over the
years; this version consists of code written primarily by:
sudo
distribution (https://www.sudo.ws/contributors.html) for an exhaustive list of
people who have contributed to sudo
.
visudo
allows shell escapes.
visudo
,
please 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 file distributed with
sudo
or https://www.sudo.ws/license.html
for complete details.