DateTime is also up for the job.

use strict;
use warnings;
use DateTime::Format::Strptime;

my $str = '2007/07/17 13:21';
my $parser =
  DateTime::Format::Strptime->new( pattern => '%Y/%m/%d %H:%M' );
my $dt = $parser->parse_datetime( $str );
print $dt->epoch;
__END__
C:\src\perl\perlmonks\627080>perl -w 627080.pl
1184678460
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