>perl -wMstrict -le
"my $str1 = q/It is a guide to action which ensures that the /
          . q/military always obey the commands of the party./
          ;
 ;;
 my $n = 0;
 while ($str1 =~ m{ (?= (\b \S+ \s+ \S+ \s+ \S+ \b)) }xmsg) {
   my $t1 = $1;
   print qq{$t1};
   $n++;
   }
 ;;
 print qq{No of matching is: $n};
"
It is a
is a guide
a guide to
guide to action
to action which
action which ensures
which ensures that
ensures that the
that the military
the military always
military always obey
always obey the
obey the commands
the commands of
commands of the
of the party
No of matching is: 16