$ cat var_gen.pl
#!/usr/bin/env perl
while (<>) {
    chomp;
    my $number = length;
    print "$number\n";
}

##</code><code>##

$ cat var_out.pl
#!/usr/bin/env perl
while (<>) {
    print "Got $_"
}

##</code><code>##

$ var_gen.pl | var_out.pl
1
12
123
1234
12345
Got 1
Got 2
Got 3
Got 4
Got 5