Many thanks to Peng and Philip for their extraquick answer, but I didn't make myself clear. I am looking for a *generic* way to verify on *linux* if a generic CD I got, already burned, matches the ISO checksum which I found online. I have a linux only box, and I need to do this in general even with CDs found on magazines, or coming, by third or fourth hand, maybe after weeks, by friends of friends of.... The arrival of Shrike was just the prompt to ask it, but in general I cannot tell to somebody "check it on windows for me" So, how can I do it myself? Thanks again in advance, Marco Fioretti -- Marco Fioretti m.fioretti, at the server inwind.it Red Hat for low memory http://www.rule-project.org/en/ Needs are a function of what other people have.