Start_Time         | End Time        | TEXT
2009-07-22 08:00:00|2009-07-22 08:00:00|blablalblabla
2009-07-22 01:00:00|2009-07-22 01:00:00|blablalblabla
2009-07-22 08:00:00|2009-07-22 21:00:00|blablalblabla
2009-07-22 23:00:00|2009-07-23 00:00:00|blablalblabla
2009-07-22 23:00:00|2009-07-23 02:00:00|blablalblabla

##</code><code>##


my @hours (1, 11) ;  # Hours to check

open (FILE,"file.txt") or die "$!;";

<FILE>;  # Skip first line

while (<FILE>){  # Correction after [ack] comment
   chomp;
   my ($start_date,$stop_date,$text) = split '|';

   print "\nInterval $start_date - $stop_date\n";
   foreach my $hour(@hours){
     if( ($start_date to $stop_date) contains $hour){ # pseudo code
        print "Hour $hour: Match";
     }else{
        print "Hour $hour:Not Match";
     }
}

close(FILE);


##</code><code>##

Interval 2009-07-22 08:00:00 - 2009-07-22 08:00:00
Hour 1 :Not Match
Hour 11:Not Match

Interval 2009-07-22 01:00:00 - 2009-07-22 01:00:00
Hour 1 :Match
Hour 11:Not Match

Interval 2009-07-22 08:00:00 - 2009-07-22 21:00:00
Hour 1 :Not Match
Hour 11:Match

Interval 2009-07-22 23:00:00 - 2009-07-23 00:00:00
Hour 1 :Not Match
Hour 11:Not Match


Interval 2009-07-22 23:00:00 - 2009-07-23 02:00:00
Hour 1 :Match
Hour 11:Not Match