# First file ==================================
#!/usr/bin/perl
# file: write_ten.pl
# Figure 2.3: Write ten lines of text to a pipe

use strict;
open (PIPE,"| read_three.pl") or die "Can't open pipe: $!";
select PIPE; $|=1; select STDOUT;

my $count = 0;
for (1..10) {
  warn "Writing line $_\n";
  print PIPE "This is line number $_\n" and $count++;
  sleep 1;
}
close PIPE or die "Can't close pipe: $!";

print "Wrote $count lines of text\n";

# SECOND FILE ===============================
#!/usr/bin/perl
# file: read_three.pl
# Figure 2.4: Read three lines of text from standard input

use strict;
for (1..3) {
  last unless defined (my $line = <>);
  warn "Read_three got: $line";
}