# calling program: foo.pl
#!/usr/bin/perl -w
use strict;
use MyPack;
print "$foo\n";
bar();
__END__


# module file: MyPack.pm
package MyPack;
require Exporter;
@ISA    = qw/Exporter/;
@EXPORT = qw/$foo bar/;
use strict;

$MyPack::foo = 42;
sub bar {
    print "This is MyPack::bar, who's calling please?\n";
}
1;
__END__


# example run:
[jandrew:~]$ perl foo.pl 
42
This is MyPack::bar, who's calling please?