Pipes in Perl

#!/usr/bin/perl

open ORA, "| /u01/app/oracle/product/11.1.0/db_1/bin/sqlplus -s $user/$pass" or die "Can't pipe to sqlplus: $!";
print ORA "set trimspool on pagesize 500 linesize 200 colsep ' '\n";
print ORA "spool output.txt\n";
print ORA "select * from tab;\n";
print ORA "spool off\n";
print ORA "exit\n";
close ORA;

#-- list the processes running on your system
open(PS,"ps -e -o pid,stime,args |") || die "Failed: $!\n";
while ( )
{
print $_;
}