UNZIP: Exit Codes, VMS Mapping, and Known Bugs

compression method or encryption with an unknown password. 2 a generic error in the zipfile format was detected. Pro‐ cessing may have completed successfully anyway; some bro‐ ken zipfiles created by other archivers have simple work‐ arounds. 3 a severe error in the zipfile format was detected. Pro‐ cessing probably failed immediately. 4 unzip was unable to allocate memory for one or more buffers during program initialization. 5 unzip was unable to allocate memory or unable to obtain a tty to read the decryption password(s). 6 unzip was unable to allocate memory during decompression to disk. 7 unzip was unable to allocate memory during in‐memory de‐ compression. 8 [currently not used] 9 the specified zipfiles were not found. 10 invalid options were specified on the command line. 11 no matching files were found. 50 the disk is (or was) full during extraction. 51 the end of the ZIP archive was encountered prematurely. 80 the user aborted unzip prematurely with control‐C (or sim‐ ilar) 81 testing or extraction of one or more files failed due to unsupported compression methods or unsupported decryption. 82 no files were found due to bad decryption password(s). (If even one file is successfully processed, however, the exit status is 1.) VMS interprets standard Unix (or PC) return values as other, scarier‐ looking things, so unzip instead maps them into VMS‐style status codes. The current mapping is as follows: 1 (success) for normal exit, 0x7fff0001 for warning errors, and (0x7fff000? + 16*normal_un‐ zip_exit_status) for all other errors, where the ‘?’ is 2 (error) for unzip values 2, 9‐11 and 80‐82, and 4 (fatal error) for the remaining ones (3‐8, 50, 51). In addition, there is a compilation option to ex‐ pand upon this behavior: defining RETURN_CODES results in a human‐read‐ able explanation of what the error status means. BUGS Multi‐part archives are not yet supported, except in conjunction with zip. (All parts must be concatenated together in order, and then ‘‘zip -F’’ (for zip 2.x) or ‘‘zip -FF’’ (for zip 3.x) must be performed on the concatenated archive in order to ‘‘fix’’ it. Also, zip 3.0 and later can combine multi‐part (split) archives into a combined single‐file archive using ‘‘zip -s- inarchive ‐O outarchive’’. See the zip 3 manual page for more information.) This will definitely be corrected in the next major release. Archives read from standard input are not yet supported, except with funzip (and then only the first member of the archive can be extracted). Archives encrypted with 8‐bit passwords (e.g., passwords with accented European characters) may not be portable across systems and/or other archivers. See the discussion in DECRYPTION above. unzip’s -M (‘‘more’’) option tries to take into account automatic wrap‐ ping of long lines. However, the code may fail to detect the correct wrapping locations. First, TAB characters (and similar control se‐ quences) are not taken into account, they are handled as ordinary print‐ able characters. Second, depending on the actual system / OS port, un‐ zip may not detect the true screen geometry but rather rely on "commonly used"

This section details the exit status codes returned by Unzip, providing explanations for various errors such as zipfile format issues, memory allocation failures, missing files, and decryption problems. It also describes how VMS interprets these codes and maps them to VMS-style status codes. Additionally, it lists known bugs and limitations of Unzip, including the lack of support for multi-part archives (except with zip), archives read from standard input, and potential issues with 8-bit password encryption.