UNZIP: Further Examples, Tips, and Diagnostics

globbing is turned on). To extract all FORTRAN and C source files, regardless of case (e.g., both *.c and *.C, and any makefile, Makefile, MAKEFILE or similar): unzip -C source.zip "*.[fch]" makefile ‐d /tmp To extract any such files but convert any uppercase MS‐DOS or VMS names to lowercase and convert the line‐endings of all of the files to the lo‐ cal standard (without respect to any files that might be marked ‘‘bi‐ nary’’): unzip -aaCL source.zip "*.[fch]" makefile ‐d /tmp To extract only newer versions of the files already in the current di‐ rectory, without querying (NOTE: be careful of unzipping in one time‐ zone a zipfile created in another‐‐ZIP archives other than those created by Zip 2.1 or later contain no timezone information, and a ‘‘newer’’ file from an eastern timezone may, in fact, be older): unzip -fo sources To extract newer versions of the files already in the current directory and to create any files not already there (same caveat as previous exam‐ ple): unzip -uo sources To display a diagnostic screen showing which unzip and zipinfo options are stored in environment variables, whether decryption support was com‐ piled in, the compiler with which unzip was compiled, etc.: unzip -v In the last five examples, assume that UNZIP or UNZIP_OPTS is set to ‐q. To do a singly quiet listing: unzip -l file.zip To do a doubly quiet listing: unzip -ql file.zip (Note that the ‘‘.zip’’ is generally not necessary.) To do a standard listing: unzip --ql file.zip or unzip -l-q file.zip or unzip -l--q file.zip (Extra minuses in options don’t hurt.) TIPS The current maintainer, being a lazy sort, finds it very useful to de‐ fine a pair of aliases: tt for ‘‘unzip -tq’’ and ii for ‘‘unzip -Z’’ (or ‘‘zipinfo’’). One may then simply type ‘‘tt zipfile’’ to test an archive, something that is worth making a habit of doing. With luck un‐ zip will report ‘‘No errors detected in compressed data of zip‐ file.zip,’’ after which one may breathe a sigh of relief. The maintainer also finds it useful to set the UNZIP environment vari‐ able to ‘‘-aL’’ and is tempted to add ‘‘-C’’ as well. His ZIPINFO vari‐ able is set to ‘‘-z’’. DIAGNOSTICS The exit status (or error level) approximates the exit codes defined by PKWARE and takes on the following values, except under VMS: 0 normal; no errors or warnings detected. 1 one or more warning errors were encountered, but process‐ ing completed successfully anyway. This includes zipfiles where one or more files was skipped due to unsupported 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.

The text provides additional examples of using Unzip, including extracting files with case-insensitivity, converting filenames to lowercase, converting line endings, and extracting only newer versions of files. It also demonstrates how to use environment variables and aliases for convenience. Furthermore, it explains the exit status codes that Unzip returns, indicating different levels of errors or warnings encountered during the process.