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From: art@pilikia.pegasus.com (Art Neilson)
Newsgroups: comp.unix.shell
Subject: Re: awk question
Message-ID: <1991Feb28.095620.21291@pilikia.pegasus.com>
Date: 28 Feb 91 09:56:20 GMT
References: <62322@eerie.acsu.Buffalo.EDU>
Organization: Pilikia, Honolulu
Lines: 38

In article <62322@eerie.acsu.Buffalo.EDU> haozhou@acsu.buffalo.edu (Hao Zhou) writes:
>I am using awk to print some selected lines from a text file. What I
>want to to is to hold off the current line until next line comes in
>and a certain condition is satisfied before printing both lines. So I
>need to store the current line in some variable as follows:
>
>	prev = 'initialization'
>	awk '{{if (condition) \
>		printf("%s \n %s \n", $prev, $0)} 
>	      {prev=$0}}'
>
>However the variable prev doesn't store the previous line. Instead the
>printf prints out twice the current line. What am I doing wrong?
>
>Thanks for any help on this problem.
>
>
>	Hao
>	
>-- 
>Internet:haozhou@acsu.buffalo.edu BITNET:haozhou%acsu.buffalo.edu@UBVM.BITNET
>UUCP: rutgers!ub!haozhou

All your curly braces are quite confusing.
This looks like what you're trying to do.

awk '
BEGIN {
	prev = 'initialization'
}
{
	if (condition)
		printf("%s \n %s \n", prev, $0)
	prev = $0
}'
-- 
Arthur W. Neilson III		| INET: art@pilikia.pegasus.com
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