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

sub regex {
    my $file = 'test.rtf';
    my $substr = 'Date of Last Update:';

    open( my $in ,"<", $file) 
	or die "Can not open file: ".$file.": $!\n";

    while ( <$in> ) {
	chomp($_);
	# Solution: 1 substring
	# if (index($_, $substr) != -1) {
	# Solution: 2 regex string{times,} at least string 1s
	# if( $_ =~ /(?:$substr){1,}/) {
	# Solution: 3 regex match string or more times: +
	# if( $_ =~ /(?:$substr)+/ ) {
	# Solution: 4 quotemeta match string
	if( $_ =~ /\Q$substr\E/ ) {
	    chop($_); # I use chop to remove the last trailing character (})
	    print $_ . "\n";
	    push(@_,$_);
	    next;
	}
    }
    # Count the number of signature lines

    print "I found the string: ".@_." time(s)!\n";
    close ($in)
	or die "Can not close file: ".$file.": $!\n";
}

regex();

sub my_grep {

    # Solution 5: grep in perl!!!! (My favorite)
    my $file = 'test.rtf';
    my $substr = 'Date of Last Update:';

    open(my $in ,"<", $file) 
	or die "Can not open file: ".$file.": $!\n";

    @_ = <$in>;

    chomp @_;

    my @out = grep { $_ =~ /Date of Last Update:/ } @_;

    print "I found the string: ".@out." time(s)!\n";
    close ($in)
	or die "Can not close file: ".$file.": $!\n";
}

# &my_grep();