while ($info=~ /(\w+ (-?\d+ )+)/)
## LOOP while  $info  m//atches pattern
## pattern is ...
{
    my $info =~ s/(\w+ (-?\d+ )+)//;
## does nothing in effect 
## technically, creates new variable $info
## attempts to remove using s///ubstitution operator
## pattern from $info
## attempts to replace pattern with nothing
## $info is empty new variable
## so the pattern will not match
## and no substitution will be performed

}