gunzip

Is there a faster solution than my actual 'zcat' solution to gunzip files with Perl? A little benchmark: #!/usr/bin/perl use strict; use warnings; use Benchmark qw(cmpthese timethese); use IO::Uncompress::Gunzip qw(gunzip); my $re = qr/test/; my $bench = timethese($ARGV[1], { zcat => sub { if (defined open(my $FILE, "-|", "zcat " . $ARGV[0])) { while (<$FILE>) { print $_ if ($_ =~ $re); } close($FILE); } }, io_gunzip => sub { my $z = new IO::Uncompress::Gunzip $ARGV[0]; while (<$z>) { print $_ if ($_ =~ $re); } }, io_gunzip_getline => sub { my $z = new IO::Uncompress::Gunzip $ARGV[0]; while

For working with images that are stored as .gz files (my image processing software can read .gz files for shorter/smaller disk time/space) I need to check the header of each file. The header is just a small struct of a fixed size at the start of each image, and for images that are not compressed, checking it is very fast. For reading the compressed images, I have no choice but to decompress the whole file and then check this header, which of course slows down my program. Would it be possible to read the first segment of a .gz file (say a couple of K), decompress this segment and read the

How to get the first few lines from a gziped file ? I tried zcat, but its throwing an error zcat CONN.20111109.0057.gz|head CONN.20111109.0057.gz.Z: A file or directory in the path name does not exist. zcat(1) can be supplied by either compress(1) or by gzip(1) . On your system, it appears to be compress(1) -- it is looking for a file with a .Z extension. Switch to gzip -cd in place of zcat and your command should work fine: gzip -cd CONN.20111109.0057.gz | head On some systems (e.g., Mac), you need to use gzcat . On a mac you need to use the < with zcat: zcat < CONN.20111109.0057.gz|head If a