format_c@server:~/perl_scripts> cat test.pl && perl test.pl
#!/usr/bin/perl
use strict;
use Time::Local;
use warnings;
my @weekdays = qw/So Mo Di Mi Do Fr Sa/;
my @date = qw/07 2004/;
my ($firstweekday) = (localtime(timelocal(0,0,0,1,$date[0]-1,$date[1]-1900)))[6];

print $weekdays[$firstweekday],"\n";
Do
format_c@server:~/perl_scripts>