G'day crazy-duck,

Welcome to the monastery.

You should set up dummy data to test your solution. That data should include boundary conditions (e.g exactly 6am, 1 minute before, and 1 minute after). You also need to be clearer about the range: "between 6pm to 6am" inclusive? exclusive? other?

In the code you posted, there's some problems:

• See the open documentation for the preferred way to open a file for reading. Something like: open my $fh, '<', $filename ...
• while (<FILE>) (which would become while (<$fh>)) reads a record at a time. Given you're reading a (potentially very long) log file, this is a good idea.
• After reading the first record, you read all the remaining records into an array with @ARRAY = <FILE>. This is a bad idea for the same reason that reading a record at a time was a good idea. Also, as there's now no more records to read, the while loop won't reiterate (i.e. in total, it only loops once).
• There's some garbage in the close FILE line. Possibly a typo; however, you need to post exactly the code you're running: we can't guess what you meant to write. See the close documentation, if necessary.

Identifying the lines you want is fairly straightforward. For something this simple, I wouldn't recommend a CPAN module nor a complex calculation. A plain comparison, which is easy to read and, if necessary, easy to adjust, is all that's required.

#!/usr/bin/env perl

use strict;
use warnings;

while (<DATA>) {
    my ($time, $hours, $mins) = /@((\d\d):(\d\d))/;
    next unless $hours < 6 || $hours > 17 || $time eq '06:00';
    # A line we want is in $_ - process it here, e.g.
    print;
}

__DATA__
**FAILED PROD** - BUGS - 08/26/13 @00:00 - ... WANTED 1
**FAILED PROD** - BUGS - 08/26/13 @00:01 - ... WANTED 2
**FAILED PROD** - BUGS - 08/26/13 @05:59 - ... WANTED 3
**FAILED PROD** - BUGS - 08/26/13 @06:00 - ... WANTED 4
**FAILED PROD** - BUGS - 08/26/13 @06:01 - ... NOT WANTED 1
**FAILED PROD** - BUGS - 08/26/13 @12:00 - ... NOT WANTED 2
**FAILED PROD** - BUGS - 08/26/13 @17:59 - ... NOT WANTED 3
**FAILED PROD** - BUGS - 08/26/13 @18:00 - ... WANTED 5
**FAILED PROD** - BUGS - 08/26/13 @18:01 - ... WANTED 6
**FAILED PROD** - BUGS - 08/26/13 @23:59 - ... WANTED 7
**FAILED PROD** - BUGS - 08/26/13 @24:00 - ... WANTED 8 (LAST)
[download]

Output:

**FAILED PROD** - BUGS - 08/26/13 @00:00 - ... WANTED 1
**FAILED PROD** - BUGS - 08/26/13 @00:01 - ... WANTED 2
**FAILED PROD** - BUGS - 08/26/13 @05:59 - ... WANTED 3
**FAILED PROD** - BUGS - 08/26/13 @06:00 - ... WANTED 4
**FAILED PROD** - BUGS - 08/26/13 @18:00 - ... WANTED 5
**FAILED PROD** - BUGS - 08/26/13 @18:01 - ... WANTED 6
**FAILED PROD** - BUGS - 08/26/13 @23:59 - ... WANTED 7
**FAILED PROD** - BUGS - 08/26/13 @24:00 - ... WANTED 8 (LAST)
[download]