[johnsca@cory johnsca]# cat tst.pl
#!/usr/bin/perl

my $run = $ARGV[0] + 1;

chomp(my $val = <STDIN>);

print "Test #$run: '$val'\n";

system('./tst.pl', $run) unless $run >= 3;
[johnsca@cory johnsca]# ./tst.pl
foo
Test #1: 'foo'
bar
Test #2: 'bar'
baz
Test #3: 'baz'
[johnsca@cory johnsca]# cat tst.inp
foo
bar
baz
quux
[johnsca@cory johnsca]# ./tst.pl < tst.inp
Test #1: 'foo'
Test #2: ''
Test #3: ''
[johnsca@cory johnsca]# cat tst.inp | ./tst.pl
Test #1: 'foo'
Test #2: ''
Test #3: ''