There are times when we download a file (say an ISO image) hosted somewhere on the Internet only to find that it’s not working as expected (or, at all). There could be multiple reasons behind this, with one among them being file corruption (the file got corrupted during the download process, or the original, hosted file itself was corrupt). But how to confirm that such a corruption has occurred?
In Linux, there’s a command line tool that you can use to create/verify checksum. It’s dubbed cksum. Most vendors offer a checksum (or a checksum-like code) corresponding to the file(s) being downloaded. If the file doesn’t behave in an expected way, user’s can recompute the file’s checksum and compare it with the original checksum provided by the vendor to see if the file is intact or got corrupted.
Well, there does exist a solution to this problem. In most cases, what’s done is, when the file is originally created, a checksum is computed which is unique to that file. Even if there’s a slight change in the file, the checksum – when computed again – changes.
So most vendors offer a checksum (or a checksum-like code) corresponding to the file(s) being downloaded. If the file doesn’t behave in expected way, user’s can recompute the file’s checksum and compare it with the original checksum provided by the vendor to see if the file is intact or got corrupted.
Read more at HowtoForge
