pod2usage will print a usage message for the invoking script (using its
embedded POD documentation) and then exit the script with the desired exit
status. The usage message printed may have any one of three levels of
"verboseness": If the verbose level is 0, then only a synopsis is printed.
If the verbose level is 1, then the synopsis is printed along with a
description (if present) of the command line options and arguments. If the
verbose level is 2, then the entire manual page is printed.