This little gem comes from the logwatch script that reads the fail2ban log. I'm not getting any output, and put the script under the debugger.

while (defined(my $ThisLine = <STDIN>)) {
    if ( $Debug >= 5 ) {
        print STDERR "DEBUG($DebugCounter): $ThisLine";
        $DebugCounter++;
    }
    chomp($ThisLine);
    if ( ($ThisLine =~ /..,... DEBUG: /) or
         ($ThisLine =~ /..,... \S*\s*: DEBUG /) or # syntax of 0.7.? f
+ail2ban
         ($ThisLine =~ /..,... INFO: (Fail2Ban v.* is running|Exiting|
+Enabled sections:)/) or
         ($ThisLine =~ /INFO\s+Log rotation detected for/) or
         ($ThisLine =~ /INFO\s+Jail.+(?:stopped|started|uses poller)/)
+ or
         ($ThisLine =~ /INFO\s+Changed logging target to/) or
         ($ThisLine =~ /INFO\s+Creating new jail/) or
         ($ThisLine =~ /..,... \S+\s*: INFO\s+(Set |Socket|Exiting|Gam
+in|Created|Added|Using)/) or # syntax of 0.7.? fail2ban
         ($ThisLine =~ /..,... WARNING: Verbose level is /) or
         ($ThisLine =~ /..,... WARNING: Restoring firewall rules/)
       )
    {
        if ( $Debug >= 6 ) {
            print STDERR "DEBUG($DebugCounter): line ignored\n";
        }
    } elsif ( my ($Service,$Host,$NumFailures) = ($ThisLine =~ m/INFO:
+ (\S+): (.+) has (\d+) login failure\(s\). Banned./)) {
        if ($Debug >= 4) {
            print STDERR "DEBUG: Found host $Host trying to access $Se
+rvice - failed $NumFailures times\n";
        }
        push @{$ServicesBans{$Service}{$Host}{'Failures'}}, $NumFailur
+es;
    } elsif ( my ($Service,$Host) = ($ThisLine =~ m/ ERROR:\s(.*):\s(\
+S+)\salready in ban list/)) {
         $ServicesBans{$Service}{$Host}{'AlreadyInTheList'}++;
    } elsif ( my ($Service,$Host) = ($ThisLine =~ m/WARNING\s*\[(.*)\]
+\s*(\S+)\s*already banned/)) {
       $ServicesBans{$Service}{$Host}{'AlreadyInTheList'}++;
    } elsif ( my ($Service,$Host) = ($ThisLine =~ m/ WARNING:\s(.*):\s
+ReBan (\S+)/)) {
            $ServicesBans{$Service}{$Host}{'ReBan'}++;
    } elsif ($ThisLine =~ / ERROR:?\s*(Execution of command )?\'?iptab
+les/) {
            push @IptablesErrors, "$ThisLine\n";
    } elsif ($ThisLine =~ /ERROR.*returned \d+$/) {
       push @ActionErrors, "$ThisLine\n";
    } elsif (($ThisLine =~ /..,... WARNING: \#\S+ reinitialization of 
+firewalls/) or
            ($ThisLine =~ / ERROR\s*Invariant check failed. Trying to 
+restore a sane environment/)) {
            $ReInitializations++;
    } elsif ($ThisLine =~ /..,... WARNING:  is not a valid IP address/
+) {
        # just ignore - this will be fixed within fail2ban and is harm
+less warning
    }
    else
    {
        # Report any unmatched entries...
        push @OtherList, "$ThisLine\n";
    }
}
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When I run this under the debugger, and I advance using the "s" command, should I expect the debugger to stop on each of the elsif statements before evaluating it, or should it only stop if the argument is true?