Edits sudo's control file sudoers in the vi editor. Using visudo instead of editing directly prevents two users from performing edits at once. Also, visudo will not save edits to sudoers if they are not syntactically correct.
Syntax check on the file's contents, without editing. Exits with 0 if it's valid, or 1 if not.
Specifies an alternate location for the sudoers file.
Quiet mode. When used with -c, do not print errors.
Strict checking. An alias used before it is defined is an error.
Print the version number.