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regexperl

How can I grab multiple lines after a matching line in Perl?

I'm parsing a large file in Perl line-by-line (terminated by \n), but when I reach a certain keyword, say "TARGET", I need to grab all the lines between TARGET and the next completely empty line.

So, given a segment of a file:

Line 1
Line 2
Line 3
Line 4 Target
Line 5 Grab this line
Line 6 Grab this line
\n

It should become:
Line 4 Target
Line 5 Grab this line
Line 6 Grab this line

The reason I'm having trouble is I'm already going through the file line-by-line; how do I change what I delimit by midway through the parsing process?

Solution

  • You want something like this:

    my @grabbed;
while (<FILE>) {
    if (/TARGET/) {
        push @grabbed, $_;
        while (<FILE>) {
            last if /^$/;
            push @grabbed, $_;
        }
    }
}