my %seeking = (
    $switchfqdn => { regex => qr/^fc.*?$hba_wwn/ },
    ...
);

for my $filename ( keys %seeking ) {
    open my $in, '<', $filename or do {
        warn "$filename: $!\n";
        next;
    };
    while (<$in>) {
        if ( /$seeking{$filename}{regex}/ ) {
            $seeking{$filename}{found} = $_;
            last;
        }
    }
    if ( $seeking{$filename}{found} ) {
        print "found in $filename: $seeking{$filename}{found}";
    else {
        warn "no matches in $filename for $seeking{$filename}{regex}\n";
    }
}