"Robert Klemme" <bob.news / gmx.net> writes:

> Damien Wyart wrote:
>> Many thanks to everyone who responded, the answers are very
>> interesting and enlightening !
>
> As far as I can see noone used the Hash with block feature.  So here it
> is:
>
> ruby -e 'h=Hash.new(){|ha,l| puts l;ha[l.freeze]=1};ARGF.each {|l| h[l]}'

Or, using my favorite unknown Hash method, fetch with a block:

  ruby -ne '($h||={}).fetch($_){puts $h[$_]=$_}'

>     robert
-- 
Christian Neukirchen  <chneukirchen / gmail.com>  http://chneukirchen.org