Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!unido!quando!omerzu
From: omerzu@quando.quantum.de (Thomas Omerzu)
Newsgroups: comp.unix.questions
Subject: Re: Deleting (Only) First Blank Line in File
Message-ID: <1607@quando.quantum.de>
Date: 1 Jul 90 22:15:37 GMT
References: <1651@fallst.UUCP> <819@ehviea.ine.philips.nl>
Reply-To: omerzu@quando.quantum.de (Thomas Omerzu)
Distribution: comp
Organization: Quantum GmbH, Dortmund, W-Germany
Lines: 29


In article <819@ehviea.ine.philips.nl> leo@ehviea.UUCP (Leo de Wit) writes:

>In article <1651@fallst.UUCP> tkevans@fallst.UUCP (Tim Evans) writes:
>|Can someone help me to delete the _first_ occurring blank line of a file
>|(whereever it occurs) without deleting subsequent ones?
>|
>|You'd think the following would work, but it doesn't:
>|
>|	sed 's/^$//1' foo > newfoo
>
>Sure. It isn't valid sed syntax.


NO! It is valid sed syntax.

The reason, that this does not work as supposed is different:
the pattern  /^$/  matches  any empty line.
On the first occurency (indicated by '1'), this emptiness is replaced
by //, i.e. nothing, and the line is  p r i n t e d.
And this is the actual problem: /^$/ does  n o t  include the '\n',
which ist created by printing the empty line.


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