Re: need to extract top and bottom lines...

The idea here is to keep a context, by storing the previous line:

open (DIFFR, "/tmp/log.diff") or die "Could not open ;/tmp/log.diff\n"
+;
my $prev = <DIFFR>;
while (my $curr = <DIFFR>) {
   print "$prev$curr" if $curr =~ /ERROR/;
   $prev = $curr;
}
[download]

-Mark

Comment on Re: need to extract top and bottom lines... Download Code

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Re^2: need to extract top and bottom lines... by holli (Abbot) on Dec 15, 2004 at 15:42 UTC
how about a one-liner? perl -ne "print qq($last\n$_) if /ERROR/; $last=$_" logfile>csvfile	[reply]
Re^3: need to extract top and bottom lines... by johngg (Canon) on Dec 16, 2004 at 10:11 UTC
You can add a little logic to the one-liner to cope with more general cases where some ERROR messages don't span two lines (assuming messages all start with a timestamp). `perl -ne 'sub BEGIN {$l="";}$l=$_, next unless /ERROR/;print /^[^12]/ +? "$l$_" : $_;$l=$_;' some.log` [download] Not Y3K compliant. JohnGG ~~Note: something is eating the square brackets around the character class ^12 for some reason. Code tags don't help.~~	[reply] [d/l]
Re^4: need to extract top and bottom lines... by johngg (Canon) on Dec 16, 2004 at 11:20 UTC
Oops, something ate the square brackets around the negated character class ^12. Maybe code tags will help, maybe not. `perl -ne 'sub BEGIN {$l="";}$l=$_, next unless /ERROR/;print /^[^12]/ +? "$l$_" : $_;$l=$_;' some.log` [download] Johngg	[reply] [d/l]