'unzoo' is a zoo archive extractor. A zoo archive is a file that contains several files, called its members, usually in compressed form to save space. 'unzoo' can list all or selected members or extract all or selected members, i.e., uncompress them and write them to files. It cannot add new members or delete members. For this you need the zoo archiver, called 'zoo', written by Rahul Dhesi.