if (/^\S+/) {
    print "$&\n";
  }

##</code><code>##

  if (/^(\S+)\s+/) {
    print "$1\n";
  }

##</code><code>##

xcommand | perl -nae 'print $F[0],"\n"'

##</code><code>##

  my $command="xcommand";
  open(CMD, "$command |") or die "Error: $!\n";
  while(<CMD>) {
    print (split(" "))[0]."\n"; # or whatever else
  }
  close(CMD);