BUGS The -F option is not necessary given the command line variable assignment feature; it remains only for backwards compatibility.

EXAMPLES Print and sort the login names of all users:

            BEGIN     { FS = ":" }
                 { print $1 | "sort" }

The above is from the GAWK manpage. FWIW, the first example under EXAMPLES uses FS not -F.

There is nothing wrong with using FS instead of -F.