d (Delete) command
Deletes files from archive.
7z d archive.zip *.bak -r
deletes *.bak files from archive archive.zip.
7-Zip doesn't use the system wildcard parser. 7-Zip doesn't follow the archaic rule by which *.* means any file. 7-Zip treats *.* as matching the name of any file that has an extension. To process all files, you must use a * wildcard.