use strict;
use warnings;

##</code><code>##

my $file = 'C:/Work/PAYROLL>TXT';
open(my $fh, '<', $file) or die "Cannot open file '$file' for reading: $!";

##</code><code>##

#! perl
use strict;
use warnings;

my $start_day = '1/17';

while (my $payperiod = <DATA>)
{
    if ($payperiod =~ /$start_day/ .. 0)
    {
        print $., ' '. $payperiod;
    }
}

__DATA__
start: 1/3
aaa
end:   1/16
start: 1/17
bbb
end:   1/30
start: 1/31
ccc
end:   2/13

##</code><code>##

 1:26 >perl 1110_SoPW.pl
4 start: 1/17
5 bbb
6 end:   1/30
7 start: 1/31
8 ccc
9 end:   2/13

 1:26 >