use DBD::Oracle qw(:ora_session_modes);   # Import ORA_SYSDBA constant

$dbh = DBI->connect('dbi:Oracle',"","",{
      PrintError => 0,
      AutoCommit => 1,
      ora_session_mode => ORA_SYSDBA });
if (! $dbh) {print "can't connect to instance as sysdba\n";exit;}

my $res = system("cp /tmp/pfile.ora /tmp/pfile.new.ora");
if ($res) {
       print "Unable to copy file\n$!\n";
}