From perlipc, use the popen()-like version of open.

Using open() for IPC
       Perl's basic open() statement can also be used for unidirection
+al interprocess communication by either
       appending or prepending a pipe symbol to the second argument to
+ open().  Here's how to start something up in a
       child process you intend to write to:

           open(SPOOLER, "| cat -v | lpr -h 2>/dev/null")
                           || die "can't fork: $!";
           local $SIG{PIPE} = sub { die "spooler pipe broke" };
           print SPOOLER "stuff\n";
           close SPOOLER || die "bad spool: $! $?";

       And here's how to start up a child process you intend to read f
+rom:

           open(STATUS, "netstat -an 2>&1 |")
                           || die "can't fork: $!";
           while (<STATUS>) {
               next if /^(tcp|udp)/;
               print;
[download]