From: Ryan Leavengood <leavengood@...>
Date: 2005-10-06T05:25:50+09:00
Subject: Re: One-liner removing duplicate lines

On 10/5/05, Damien Wyart <damien.wyart@free.fr> wrote:
> Hello,
>
> Converting from Perl to Ruby, I am trying to find an equivalent to this
> Perl one-liner removing duplicate lines in a file (without sorting it at
> first) :
>
>    perl -ne'$s{$_}++||print' infile >outfile
>
> I guess uniq method could be used, but I can't find how.

I tried creating a version that mimics the Perl one (because Ruby also
has the -n option), but in the end this seemed easier (and much more
readable):

ruby -e "puts IO.readlines(ARGV[0]).uniq" infile > outfile

So you are right about using uniq.

Ryan