Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!convex!convex.COM
From: tchrist@convex.COM (Tom Christiansen)
Newsgroups: comp.lang.perl
Subject: Re: Novice Question, Successive Lines
Keywords: Novice Question, Successive Lines
Message-ID: <100742@convex.convex.com>
Date: 21 Mar 90 14:32:26 GMT
References: <13447@cgl.ucsf.EDU>
Sender: usenet@convex.com
Reply-To: tchrist@convex.COM (Tom Christiansen)
Distribution: na
Organization: CONVEX Software Development, Richardson, TX
Lines: 29

In article <13447@cgl.ucsf.EDU> alonso@maxwell.mmwb.ucsf.edu (Darwin Alonso) writes:
>How would one get perl to replace two or more successive blank lines 
>with one blank line?

You can do this:

	#!/usr/bin/perl -n
	next if /^$/ && $skip++;
	print;
	$skip &= /^$/;

Or as a one liner:

    perl -n -e 'next if /^$/ && $skip++; print; $skip &= /^$/;'

Or you if you have lots of memory or little files:

    undef $/;
    $_ = <>;
    s/\n{3,}/\n\n/g;
    print;


--tom
--

    Tom Christiansen                       {uunet,uiucdcs,sun}!convex!tchrist 
    Convex Computer Corporation                            tchrist@convex.COM
		 "EMACS belongs in <sys/errno.h>: Editor too big!"