box-o-sand/perl-practice/cli/ex03/rwfakegrep.pl

#!/usr/bin/env perl
use strict;
use warnings;

use File::Basename;
use English qw/$PROGRAM_NAME/;

my $basename = basename($0);
my $USAGE = <<USAGE
Usage: $basename <infile> <outfile>
USAGE
;


sub show_last_chapter_with_nlines {
    my ($ch, $nlines) = @_;
    print "Chapter $ch has $nlines lines\n";
}


sub main {
    open(INFILE, '<', $ARGV[0]) or die "$USAGE\n$!";
    open(OUTFILE, '>', $ARGV[1]) or die "$USAGE\n$!";

    my $have_seen_firstchapter = 'no';
    my $nlines = 0;
    my $chline = '';
    my $ch = '';

    foreach my $inline (<INFILE>) {
        if ($inline =~ /^\s*CHAPTER.*$/) {

            $chline = "$inline";
            $ch = "$chline";
            $ch =~ s/^\s*CHAPTER\s*([0-9]*).*/$1/;
            $ch =~ s/[\r\n]//;

            if ($have_seen_firstchapter eq 'yes') {
                show_last_chapter_with_nlines($ch - 1, $nlines);
                $nlines = 0;
            } else {
                $have_seen_firstchapter = 'yes';
                $nlines = 0;
            }
            print OUTFILE $inline;
        }
        $nlines++;
    }

    show_last_chapter_with_nlines($ch, $nlines);

}


if ($PROGRAM_NAME eq __FILE__) {
    main();
}


1;
__END__