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 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.
Specify and 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.
The -h (help) option causes visudo to print 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 (‘
The -V (version) option causes visudo to print its version number and exit.
Many people have worked on sudo
over the years; this version consists of code written primarily by:
Todd C. Miller
See the CONTRIBUTORS file in the sudo
distribution (https://www.sudo.ws/sudo/contributors.html) for an exhaustive list of people who have contributed to sudo