From af137@torfree.net Sat Oct 19 16:48:10 1996
Newsgroups: comp.editors
Path: fu-berlin.de!news.mathworks.com!news-peer.gsl.net!news.gsl.net!ix.netcom.com!tor-nn1.netcom.ca!torfree!af137
From: af137@torfree.net (Al Aab)
Subject: . SED squeeze empty lines,extract titles, etc
Message-ID: <DzIELF.FKF.0.queen@torfree.net>
Organization: Toronto Free-Net
X-Newsreader: TIN [version 1.2 PL2]
Date: Sat, 19 Oct 1996 06:12:51 GMT
Lines: 47


1- as an excercise for sed gurus :  extract last line of every paragraph.

2- squeeze empty lines: 
	a- he solaris man page shows a looong script.
	b- oreilly's sed and awk has a shorter script.
	c- reminiscent of APL 1liners,
	here is the shortest sed script i've seen
	(
	 due - i guess - to the famous unix wizard :
		brian hiles whose work should be added to unix or unix faq.
	) :
			
			sed "/./,/^ *$/!d" datafile


3- to extract the first line of every paragraph :

# extract the title lines form a data file
## a title line is any line preceded by 1 or more empty lines
wrong script   : sed    "1{/./!d;};/^ *$/,/./{/./!d;}" d
correct script : sed -n "1{/./p;};/^ *$/,/./{/./p;}"   d 
-------------------------- sample data file --------------------------------
title 1 (the first line in the data file may or may not be empty)
ssssss
tttttttt

title 2
uuuu

title 3
vvvv
www


title 4
xx
yyy

title 5 (last line may or may not be empty.)
---- end of data file (notice the last line has will be considered a title) --

-- 
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al aab, seders moderator                                      sed u soon 
               it is not zat we do not see the  s o l u t i o n          
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