From: Mark Hubbart <discordantus@...>
Date: 2005-10-09T01:49:28+09:00
Subject: Re: One-liner removing duplicate lines

On 10/8/05, Mark Hubbart <discordantus@gmail.com> wrote:
> 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

As long as we're mostly obfuscated anyway, we might as well make the
whole thing punctuation:

  ruby -e'$><<([*$<]|[])' infile > outfile

cheers,
Mark
...who got into the golf round a little late