check md5 of compressed file without unpacking it completely

compression, md5

Solution

This:

gzip -d -c myfile.gz | md5sum

will stream the decompressed content into md5sum, rather than loading the whole thing into memory.

If it's a zip file, the command is `unzip -p myfile.zip | md5sum`

Problem

I want to check the integrity of a backup of a Ubuntu disk, copied with dd onto a Windows share. There is not enough space to unpack the backup. Is there a utility to calculate the md5 of a compressed file without unpacking it completely?

Original source