> In light of Lars's comment on the matter, perhaps this functionality > could be added to zip files only. Surely it can be done, considering > that numerous utilities and even Windows Explorer provide such > functionality. Are you sure they are not creating a new file in order to delete content? I recall that early zip tools (e.g. pkzip) had a mode where they would merely delete the entry from the directory, but leave the actual data in the file. Would you consider that a correct implementation? If so, *that* can be done, for zipfiles, AFAIU. > I'll spend some time the next > few days educating myself about zip files and how this might be > accomplished. Please do - you'll find that deletion from zipfiles comes in a can full of worms.