If you must do it in Perl use the Schwartzian Transform for efficiency. This avoids finding the 4th octet more than once for each line and is thus fast(er) than it might otherwise be. 

my @unsorted = <DATA>;

my @sorted =
  map{ $_->[0] } 
  sort{ $a->[1] <=> $b->[1] } 
  map { [$_, get_fourth($_) ] } 
  @unsorted;

sub get_fourth {
    local $_ = shift; 
    /\d+\.\d+\.\d+\.(\d+)/;
  return $1; 
}

print "@sorted";

__DATA__
10.194.196.55 heckyll
10.194.196.57 txwl013w
10.194.196.61 krios
10.194.196.62 stasis # dial up server
10.194.196.63 nnocdts01 # sparc 5 in wan rm
10.194.196.65 libra
10.194.196.66 legato-school
10.194.196.67 txwlxdbs nnocs002a
10.194.196.46 chqnocp01 # Laser 4MV by Joe Blow
10.194.196.47 chqnocp02
10.194.196.49 nnocrpt01
10.194.196.64 saturn
10.194.196.50 nnocgw001
10.194.196.52 nnocs002
10.194.196.53 wslkms02 wslknms0
10.194.196.54 nnocws001

[download]

Update

Changed order to ascending numrical order as per spec (I think)

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

In reply to Re: sorting /etc/hosts by tachyon
in thread sorting /etc/hosts by tmbailey123

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