Shell Programming and Scripting

$ 
$ cat testscr.pl
#!/usr/bin/perl
use Time::Local;
my $wday = $ARGV[0];
my $month = $ARGV[1];
# convert the month shortname into 0-11 number
if ( $month eq "Jan" ) { $mon = 0 }
elsif ( $month eq "Feb" ) { $mon = 1 }
elsif ( $month eq "Mar" ) { $mon = 2 }
elsif ( $month eq "Apr" ) { $mon = 3 }
elsif ( $month eq "May" ) { $mon = 4 }
elsif ( $month eq "Jun" ) { $mon = 5 }
elsif ( $month eq "Jul" ) { $mon = 6 }
elsif ( $month eq "Aug" ) { $mon = 7 }
elsif ( $month eq "Sep" ) { $mon = 8 }
elsif ( $month eq "Oct" ) { $mon = 9 }
elsif ( $month eq "Nov" ) { $mon = 10 }
elsif ( $month eq "Dec" ) { $mon = 11 };
my $mday = $ARGV[2];
# initialize time varialble and split hours (24 hr format), minutes, seconds into an array
my $time = $ARGV[3];
@time = split /:/, $time;
# if the timezone is left out of the input, the position of year becomes 5th in ARGV
my $year = $ARGV[4];

$epoch= timelocal($time[2], $time[1], $time[0], $mday, $mon, $year);
print "$epoch\n";
$ 
$ perl testscr.pl Sun Jul 31 11:58:54 2009
1249055934
$ perl testscr.pl Sun Jul 31 11:58:54
965059134
$ perl testscr.pl Sun Jul 31
965016000
$ perl testscr.pl Sun Jul
Day '' out of range 1..31 at testscr.pl line 25
$ perl testscr.pl Sun
Day '' out of range 1..31 at testscr.pl line 25
$ perl testscr.pl
Day '' out of range 1..31 at testscr.pl line 25
$ 
$