gzip -l shows incorrect data for large files (integer overflow) for example # ll backup.gz 253542016 -rw-------. 1 root root 259626991897 Jan 14 02:12 backup.gz # gzip -l backup.gz compressed uncompressed ratio uncompressed_name 259626991897 2299183104 -11192.1% backup see negative numbers in gzip -l Same thing for gzip 1.4 & gzip 1.6
This problem is known. Same problem was reported here: https://bugzilla.redhat.com/show_bug.cgi?id=116967 Problem is the uncompressed file size is stored in 32b format. See man gzip section BUGS. If you want know real uncompressed size, you can use "zcat file.gz | wc -c" - unfortunately it's very slow solution for so large files.