edits the sudoers
file in a safe fashion, analogous to vipw(8)
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
variable. This list defaults to
. Normally, visudo
does not honor the VISUAL
environment variables unless they contain an editor in the aforementioned editors list. However, if visudo
is configured with the
option or the env_editor
variable is set in sudoers
will use any the editor defines by VISUAL
. Note that this can be a security hole since it allows the user to execute any program they wish simply by setting VISUAL
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 ‘
’ to re-edit the sudoers
’ to exit without saving the changes, or ‘
’ to quit and save changes. The ‘
’ 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 run sudo
again until the error is fixed. If ‘
’ 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).
The options are as follows:
Enable check-only mode. The existing sudoers file will be checked for syntax errors, 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=sudoers
Specify an 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. In check-only mode only, the argument to -f may be ‘
-’, indicating that sudoers will be read from the standard input.
Display a short help message to the standard output and exit.
Enable quiet mode. In this mode details about syntax errors are not printed. This option is only useful when combined with the -c option.
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 (‘
Print the visudo and sudoers grammar versions and exit.
-x output_file, --export=output_file
Export a sudoers in JSON format and write it to output_file. If output_file is ‘
-’, 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.
Debugging and sudoers plugin arguments visudo
versions 1.8.4 and higher support a flexible debugging framework that is configured via
lines in the sudo.conf(5)
Starting with sudo
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
The following arguments are supported:
The sudoers_file argument can be used to override the default path to the sudoers file.
The sudoers_uid argument can be used to override the default owner of the sudoers file. It should be specified as a numeric user ID.
The sudoers_gid argument can be used to override the default group of the sudoers file. It must be specified as a numeric group ID (not a group name).
The sudoers_mode argument can be used to override the default file mode for the sudoers file. It should be specified as an octal value.
For more information on configuring sudo.conf(5)
, please refer to its manual.