如何在Perl中将Zcat与regex一起使用？

Question

I have compressed .gz files that I want to open by using:

./open.pl file.gz

Basically my goal is to only print out certain lines in the zip file that match my regex...The files are big so I just want to output to stdout for now...How would I do this? I was thinking somethig like:

while(<>){
  zcat $_ | <my regex> ????
}

Also I'm not sure about the syntax for printing lines out that match regex..

Answer 1

Here's how I've done similar

open( $handle, "zcat $ARGV[0]|" ) or die("Can't open $ARGV[0]: $!");
while( <$handle> ) {
if( /regex_pattern/ ) {
   print $_;
   }
}

Answer 2

I doubt zcat will operate correctly on newline-separated chunks of a gzipped stream. Instead, you'll want to uncompress the stream as you read it. There are at least a couple of ways to do it:

foreach my $argv (@ARGV) {
    open my $gz, "zcat $argv |";
    while (<$gz>) {
        # now $_ is an uncompressed line from the file $argv
        print if /my pattern/;
    }
}

There's probably a solution using the :gz IO layer, too, but I can't quite get that correct right now.