Question

I have an ASCII log file with some content I would like to extract. I’ve never taken time to learn Perl properly, but I figure this is a good tool for this task.

The file is structured like this:

... 
... some garbage 
... 
... garbage START
what i want is 
on different
lines 
END 
... 
... more garbage ...
next one START 
more stuff I want, again
spread 
through 
multiple lines 
END 
...
more garbage

So, I’m looking for a way to extract the lines between each START and END delimiter strings.
How can I do this?

So far, I’ve only found some examples on how to print a line with the START string, or other documentation items that are somewhat related with what I’m looking for.

Answer 1

You want the flip-flop operator (also known as the range operator) ..

#!/usr/bin/env perl
use strict;
use warnings;

while (<>) {
  if (/START/../END/) {
    next if /START/ || /END/;
    print;
  }
}

Replace the call to print with whatever you actually want to do (e.g., push the line into an array, edit it, format it, whatever). I’m next-ing past the lines that actually have START or END, but you may not want that behavior. See this article for a discussion of this operator and other useful Perl special variables.