in reply to How to print a matching line and one line above it?

As a slightly unweildy one-liner:

perl 
-ne"if(/processed/){ print($last),undef($last) if $last; print;}else{$
+last=$_}" 
junk.dat
**start xyz
File1 processed
File2 processed
**start wert
File3 processed
File4 processed

[download]
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

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Re^2: How to print a matching line and one line above it?
by vbynagari (Initiate) on Apr 20, 2011 at 00:43 UTC
    Thanks for your help. I am kinda new to perl. Can you be a bit more specific on the syntax please?
[reply]

      C:\test>type junk86.pl
#! perl -sw
use strict;

my $last;
while( <> ) {
    if( /processed/ ){
        if( $last ) {
            print( $last );
            undef( $last )
        }
        print;
    }
    else{
        $last = $_;
    }
}

C:\test>type junk.dat
**start abc
**start adl
**start xyz
File1 processed
File2 processed
**start zxcv
**start wert
File3 processed
File4 processed

C:\test>junk86 junk.dat >junk.new

C:\test>type junk.new
**start xyz
File1 processed
File2 processed
**start wert
File3 processed
File4 processed

      [download]
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]

In Section Seekers of Perl Wisdom