From: Mark Hubbart <discordantus@...>
Date: 2005-10-09T01:37:57+09:00
Subject: Re: One-liner removing duplicate lines

On 10/5/05, Ryan Leavengood <leavengood@gmail.com> wrote:
> 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.

Here's a derived version (is this really Ruby?):

  ruby -e'$><<[*$<].uniq' infile > outfile

cheers,
Mark