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UNZIP(1L) UNZIP(1L) NAME unzip - list, test and extract compressed files in a ZIP archive SYNOPSIS unzip [-Z] [-cflptuvz[abjnoqsCLMVX$]] file[.zip] [file(s) ...] [-x xfile(s) ...] [-d exdir] DESCRIPTION unzip will list, test, or extract files from a ZIP archive, commonly found on MS-DOS systems. The default behavior (with no options) is to extract into the current directory (and subdirectories below it) all files from the specified ZIP archive. A companion program, zip(1L), cre- ates ZIP archives; both programs are compatible with archives created by PKWARE's PKZIP and PKUNZIP for MS-DOS, but in many cases the program options or default behaviors differ. ARGUMENTS file[.zip] Path of the ZIP archive(s). If the file specifica- tion is a wildcard, each matching file is processed in an order determined by the operating system (or file system). Only the filename can be a wildcard; the path itself cannot. Wildcard expressions are similar to Unix egrep(1) (regular) expressions and may contain: * matches a sequence of 0 or more characters ? matches exactly 1 character [...] matches any single character found inside the brackets; ranges are specified by a beginning character, a hyphen, and an ending character. If an exclamation point or a caret (`!' or `^') follows the left bracket, then the range of characters within the brackets is complemented (that is, anything except the characters inside the brackets is considered a match). (Be sure to quote any character that might other- wise be interpreted or modified by the operating system, particularly under Unix and VMS.) If no matches are found, the specification is assumed to be a literal filename; and if that also fails, the suffix .zip is appended. Note that self-extracting ZIP files are supported, as with any other ZIP archive; just specify the .exe suffix (if any) explicitly. Info-ZIP 31 May 1997 (v5.31) 1 UNZIP(1L) UNZIP(1L) [file(s)] An optional list of archive members to be pro- cessed, separated by spaces. (VMS versions com- piled with VMSCLI defined must delimit files with commas instead. See -v in OPTIONS below.) Regular expressions (wildcards) may be used to match multi- ple members; see above. Again, be sure to quote expressions that would otherwise be expanded or modified by the operating system. [-x xfile(s)] An optional list of archive members to be excluded from processing. Since wildcard characters match directory separators (`/'), this option may be used to exclude any files that are in subdirectories. For example, ``unzip foo *.[ch] -x */*'' would extract all C source files in the main directory, but none in any subdirectories. Without the -x option, all C source files in all directories within the zipfile would be extracted. [-d exdir] An optional directory to which to extract files. By default, all files and subdirectories are recre- ated in the current directory; the -d option allows extraction in an arbitrary directory (always assum- ing one has permission to write to the directory). This option need not appear at the end of the com- mand line; it is also accepted before the zipfile specification (with the normal options), immedi- ately after the zipfile specification, or between the file(s) and the -x option. The option and directory may be concatenated without any white space between them, but note that this may cause normal shell behavior to be suppressed. In partic- ular, ``-d ~'' (tilde) is expanded by Unix C shells into the name of the user's home directory, but ``-d~'' is treated as a literal subdirectory ``~'' of the current directory. OPTIONS Note that, in order to support obsolescent hardware, unzip's usage screen is limited to 22 or 23 lines and should therefore be considered only a reminder of the basic unzip syntax rather than an exhaustive list of all possible flags. The exhaustive list follows: -Z zipinfo(1L) mode. If the first option on the com- mand line is -Z, the remaining options are taken to be zipinfo(1L) options. See the appropriate manual page for a description of these options. -A [OS/2, Unix DLL] print extended help for the DLL's programming interface (API). Info-ZIP 31 May 1997 (v5.31) 2 UNZIP(1L) UNZIP(1L) -c extract files to stdout/screen (``CRT''). This option is similar to the -p option except that the name of each file is printed as it is extracted, the -a option is allowed, and ASCII-EBCDIC conver- sion is automatically performed if appropriate. This option is not listed in the unzip usage screen. -f freshen existing files, i.e., extract only those files that already exist on disk and that are newer than the disk copies. By default unzip queries before overwriting, but the -o option may be used to suppress the queries. Note that under many operating systems, the TZ (timezone) environment variable must be set correctly in order for -f and -u to work properly (under Unix the variable is usually set automatically). The reasons for this are somewhat subtle but have to do with the differ- ences between DOS-format file times (always local time) and Unix-format times (always in GMT/UTC) and the necessity to compare the two. A typical TZ value is ``PST8PDT'' (US Pacific time with auto- matic adjustment for Daylight Savings Time or ``summer time''). -l list archive files (short format). The names, uncompressed file sizes and modification dates and times of the specified files are printed, along with totals for all files specified. If UnZip was compiled with OS2_EAS defined, the -l option also lists columns for the sizes of stored OS/2 extended attributes (EAs) and OS/2 access control lists (ACLs). In addition, the zipfile comment and indi- vidual file comments (if any) are displayed. If a file was archived from a single-case file system (for example, the old MS-DOS FAT file system) and the -L option was given, the filename is converted to lowercase and is prefixed with a caret (^). -p extract files to pipe (stdout). Nothing but the file data is sent to stdout, and the files are always extracted in binary format, just as they are stored (no conversions). -t test archive files. This option extracts each specified file in memory and compares the CRC (cyclic redundancy check, an enhanced checksum) of the expanded file with the original file's stored CRC value. -T [Unix only] set the timestamp on the archive(s) to that of the newest file in each one. This corre- sponds to zip's -go option except that it can be used on wildcard zipfiles (e.g., ``unzip -T Info-ZIP 31 May 1997 (v5.31) 3 UNZIP(1L) UNZIP(1L) \*.zip'') and is much faster. -u update existing files and create new ones if needed. This option performs the same function as the -f option, extracting (with query) files that are newer than those with the same name on disk, and in addition it extracts those files that do not already exist on disk. See -f above for informa- tion on setting the timezone properly. -v be verbose or print diagnostic version info. This option has evolved and now behaves as both an option and a modifier. As an option it has two purposes: when a zipfile is specified with no other options, -v lists archive files verbosely, adding to the basic -l info the compression method, compressed size, compression ratio and 32-bit CRC. When no zipfile is specified (that is, the complete command is simply ``unzip -v''), a diagnostic screen is printed. In addition to the normal header with release date and version, unzip lists the home Info-ZIP ftp site and where to find a list of other ftp and non-ftp sites; the target operat- ing system for which it was compiled, as well as (possibly) the hardware on which it was compiled, the compiler and version used, and the compilation date; any special compilation options that might affect the program's operation (see also DECRYPTION below); and any options stored in environment vari- ables that might do the same (see ENVIRONMENT OPTIONS below). As a modifier it works in conjunc- tion with other options (e.g., -t) to produce more verbose or debugging output; this is not yet fully implemented but will be in future releases. -z display only the archive comment. MODIFIERS -a convert text files. Ordinarily all files are extracted exactly as they are stored (as ``binary'' files). The -a option causes files identified by zip as text files (those with the `t' label in zip- info listings, rather than `b') to be automatically extracted as such, converting line endings, end-of- file characters and the character set itself as necessary. (For example, Unix files use line feeds (LFs) for end-of-line (EOL) and have no end-of-file (EOF) marker; Macintoshes use carriage returns (CRs) for EOLs; and most PC operating systems use CR+LF for EOLs and control-Z for EOF. In addition, IBM mainframes and the Michigan Terminal System use EBCDIC rather than the more common ASCII character set, and NT supports Unicode.) Note that zip's identification of text files is by no means Info-ZIP 31 May 1997 (v5.31) 4 UNZIP(1L) UNZIP(1L) perfect; some ``text'' files may actually be binary and vice versa. unzip therefore prints ``[text]'' or ``[binary]'' as a visual check for each file it extracts when using the -a option. The -aa option forces all files to be extracted as text, regard- less of the supposed file type. -b [non-VMS] treat all files as binary (no text con- versions). This is a shortcut for ---a. -b [VMS] auto-convert binary files (see -a above) to fixed-length, 512-byte record format. Doubling the option (-bb) forces all files to be extracted in this format. -B [Unix only, and only if compiled with UNIXBACKUP defined] save a backup copy of each overwritten file with a tilde appended (e.g., the old copy of ``foo'' is renamed to ``foo~''). This is similar to the default behavior of emacs(1) in many loca- tions. -C match filenames case-insensitively. unzip's phi- losophy is ``you get what you ask for'' (this is also responsible for the -L/-U change; see the rel- evant options below). Because some file systems are fully case-sensitive (notably those under the Unix operating system) and because both ZIP archives and unzip itself are portable across plat- forms, unzip's default behavior is to match both wildcard and literal filenames case-sensitively. That is, specifying ``makefile'' on the command line will only match ``makefile'' in the archive, not ``Makefile'' or ``MAKEFILE'' (and similarly for wildcard specifications). Since this does not cor- respond to the behavior of many other operat- ing/file systems (for example, OS/2 HPFS, which preserves mixed case but is not sensitive to it), the -C option may be used to force all filename matches to be case-insensitive. In the example above, all three files would then match ``make- file'' (or ``make*'', or similar). The -C option affects files in both the normal file list and the excluded-file list (xlist). -j junk paths. The archive's directory structure is not recreated; all files are deposited in the extraction directory (by default, the current one). -L convert to lowercase any filename originating on an uppercase-only operating system or file system. (This was unzip's default behavior in releases prior to 5.11; the new default behavior is identi- cal to the old behavior with the -U option, which Info-ZIP 31 May 1997 (v5.31) 5 UNZIP(1L) UNZIP(1L) is now obsolete and will be removed in a future release.) Depending on the archiver, files archived under single-case file systems (VMS, old MS-DOS FAT, etc.) may be stored as all-uppercase names; this can be ugly or inconvenient when extracting to a case-preserving file system such as OS/2 HPFS or a case-sensitive one such as under Unix. By default unzip lists and extracts such filenames exactly as they're stored (excepting truncation, conversion of unsupported characters, etc.); this option causes the names of all files from certain systems to be converted to lowercase. -M pipe all output through an internal pager similar to the Unixmore(1) command. At the end of a screenful of output, unzip pauses with a ``--More--'' prompt; the next screenful may be viewed by pressing the Enter (Return) key or the space bar. unzip can be terminated by pressing the ``q'' key and, on some systems, the Enter/Return key. Unlike Unix more(1), there is no forward- searching or editing capability. Also, unzip doesn't notice if long lines wrap at the edge of the screen, effectively resulting in the printing of two or more lines and the likelihood that some text will scroll off the top of the screen before being viewed. On some systems the number of avail- able lines on the screen is not detected, in which case unzip assumes the height is 24 lines. -n never overwrite existing files. If a file already exists, skip the extraction of that file without prompting. By default unzip queries before extracting any file that already exists; the user may choose to overwrite only the current file, overwrite all files, skip extraction of the current file, skip extraction of all existing files, or rename the current file. -N [Amiga] extract file comments as Amiga filenotes. File comments are created with the -c option of zip(1L), or with the -N option of the Amiga port of zip(1L), which stores filenotes as comments. -o overwrite existing files without prompting. This is a dangerous option, so use it with care. (It is often used with -f, however, and is the only way to overwrite directory EAs under OS/2.) -P password use password to decrypt encrypted zipfile entries (if any). THIS IS INSECURE! Many multi-user oper- ating systems provide ways for any user to see the Info-ZIP 31 May 1997 (v5.31) 6 UNZIP(1L) UNZIP(1L) current command line of any other user; even on stand-alone systems there is always the threat of over-the-shoulder peeking. Storing the plaintext password as part of a command line in an automated script is even worse. Whenever possible, use the non-echoing, interactive prompt to enter passwords. (And where security is truly important, use strong encryption such as Pretty Good Privacy instead of the relatively weak encryption provided by standard zipfile utilities.) -q perform operations quietly (-qq = even quieter). Ordinarily unzip prints the names of the files it's extracting or testing, the extraction methods, any file or zipfile comments that may be stored in the archive, and possibly a summary when finished with each archive. The -q[q] options suppress the printing of some or all of these messages. -s [OS/2, NT, MS-DOS] convert spaces in filenames to underscores. Since all PC operating systems allow spaces in filenames, unzip by default extracts filenames with spaces intact (e.g., ``EA DATA. SF''). This can be awkward, however, since MS-DOS in particular does not gracefully sup- port spaces in filenames. Conversion of spaces to underscores can eliminate the awkwardness in some cases. -U (obsolete; to be removed in a future release) leave filenames uppercase if created under MS-DOS, VMS, etc. See -L above. -V retain (VMS) file version numbers. VMS files can be stored with a version number, in the format file.ext;##. By default the ``;##'' version num- bers are stripped, but this option allows them to be retained. (On file systems that limit filenames to particularly short lengths, the version numbers may be truncated or stripped regardless of this option.) -X [VMS, Unix, OS/2, NT] restore owner/protection info (UICs) under VMS, or user and group info (UID/GID) under Unix, or access control lists (ACLs) under certain network-enabled versions of OS/2 (Warp Server with IBM LAN Server/Requester 3.0 to 5.0; Warp Connect with IBM Peer 1.0), or security ACLs under Windows NT. In most cases this will require special system privileges, and doubling the option (-XX) under NT instructs unzip to use privileges for extraction; but under Unix, for example, a user who belongs to several groups can restore files owned by any of those groups, as long as the user Info-ZIP 31 May 1997 (v5.31) 7 UNZIP(1L) UNZIP(1L) IDs match his or her own. Note that ordinary file attributes are always restored--this option applies only to optional, extra ownership info available on some operating systems. [NT's access control lists do not appear to be especially compatible with OS/2's, so no attempt is made at cross-platform portability of access privileges. It is not clear under what conditions this would ever be useful anyway.] -$ [MS-DOS, OS/2, NT] restore the volume label if the extraction medium is removable (e.g., a diskette). Doubling the option (-$$) allows fixed media (hard disks) to be labelled as well. By default, volume labels are ignored. ENVIRONMENT OPTIONS unzip's default behavior may be modified via options placed in an environment variable. This can be done with any option, but it is probably most useful with the -a, -L, -C, -q, -o, or -n modifiers: make unzip auto-convert text files by default, make it convert filenames from uppercase systems to lowercase, make it match names case- insensitively, make it quieter, or make it always over- write or never overwrite files as it extracts them. For example, to make unzip act as quietly as possible, only reporting errors, one would use one of the following com- mands: UNZIP=-qq; export UNZIP Unix Bourne shell setenv UNZIP -qq Unix C shell set UNZIP=-qq OS/2 or MS-DOS define UNZIP_OPTS "-qq" VMS (quotes for lowercase) Environment options are, in effect, considered to be just like any other command-line options, except that they are effectively the first options on the command line. To override an environment option, one may use the ``minus operator'' to remove it. For instance, to override one of the quiet-flags in the example above, use the command unzip --q[other options] zipfile The first hyphen is the normal switch character, and the second is a minus sign, acting on the q option. Thus the effect here is to cancel one quantum of quietness. To cancel both quiet flags, two (or more) minuses may be used: unzip -t--q zipfile unzip ---qt zipfile (the two are equivalent). This may seem awkward or con- fusing, but it is reasonably intuitive: just ignore the Info-ZIP 31 May 1997 (v5.31) 8 UNZIP(1L) UNZIP(1L) first hyphen and go from there. It is also consistent with the behavior of Unix nice(1). As suggested by the examples above, the default variable names are UNZIP_OPTS for VMS (where the symbol used to install unzip as a foreign command would otherwise be con- fused with the environment variable), and UNZIP for all other operating systems. For compatibility with zip(1L), UNZIPOPT is also accepted (don't ask). If both UNZIP and UNZIPOPT are defined, however, UNZIP takes precedence. unzip's diagnostic option (-v with no zipfile name) can be used to check the values of all four possible unzip and zipinfo environment variables. The timezone variable (TZ) should be set according to the local timezone in order for the -f and -u to operate cor- rectly. See the description of -f above for details. This variable may also be necessary in order for times- tamps on extracted files to be set correctly. Under Win- dows 95/NT unzip should know the correct timezone even if TZ is unset, assuming the timezone is correctly set in the Control Panel. DECRYPTION Encrypted archives are fully supported by Info-ZIP soft- ware, but due to United States export restrictions, the encryption and decryption sources are not packaged with the regular unzip and zip distributions. Since the crypt sources were written by Europeans, however, they are freely available at sites throughout the world; see the file ``Where'' in any Info-ZIP source or binary distribu- tion for locations both inside and outside the US. Because of the separate distribution, not all compiled versions of unzip support decryption. To check a version for crypt support, either attempt to test or extract an encrypted archive, or else check unzip's diagnostic screen (see the -v option above) for ``[decryption]'' as one of the special compilation options. As noted above, the -P option may be used to supply a password on the command line, but at a cost in security. The preferred decryption method is simply to extract nor- mally; if a zipfile member is encrypted, unzip will prompt for the password without echoing what is typed. unzip continues to use the same password as long as it appears to be valid, by testing a 12-byte header on each file. The correct password will always check out against the header, but there is a 1-in-256 chance that an incorrect password will as well. (This is a security feature of the PKWARE zipfile format; it helps prevent brute-force attacks that might otherwise gain a large speed advantage by testing only the header.) In the case that an incor- rect password is given but it passes the header test Info-ZIP 31 May 1997 (v5.31) 9 UNZIP(1L) UNZIP(1L) anyway, either an incorrect CRC will be generated for the extracted data or else unzip will fail during the extrac- tion because the ``decrypted'' bytes do not constitute a valid compressed data stream. If the first password fails the header check on some file, unzip will prompt for another password, and so on until all files are extracted. If a password is not known, entering a null password (that is, just a carriage return or ``Enter'') is taken as a signal to skip all further prompting. Only unencrypted files in the archive(s) will thereafter be extracted. (In fact, that's not quite true; older versions of zip(1L) and zipcloak(1L) allowed null passwords, so unzip checks each encrypted file to see if the null password works. This may result in ``false posi- tives'' and extraction errors, as noted above.) Archives encrypted with 8-bit passwords (for example, passwords with accented European characters) may not be portable across systems and/or other archivers. This problem stems from the use of multiple encoding methods for such characters, including Latin-1 (ISO 8859-1) and OEM code page 850. DOS PKZIP 2.04g uses the OEM code page; Windows PKZIP 2.50 uses Latin-1 (and is therefore incompatible with DOS PKZIP); Info-ZIP uses the OEM code page on DOS, OS/2 and Win3.x ports but Latin-1 everywhere else; and Nico Mak's WinZip 6.x does not allow 8-bit pass- words at all. UnZip 5.3 attempts to use the default char- acter set first (e.g., Latin-1), followed by the alternate one (e.g., OEM code page) to test passwords. On EBCDIC systems, if both of these fail, EBCDIC encoding will be tested as a last resort. (Since there are no known archivers that encrypt using EBCDIC encoding, EBCDIC is not tested on non-EBCDIC systems.) ISO character encod- ings other than Latin-1 are not supported. EXAMPLES To use unzip to extract all members of the archive let- ters.zip into the current directory and subdirectories below it, creating any subdirectories as necessary: unzip letters To extract all members of letters.zip into the current directory only: unzip -j letters To test letters.zip, printing only a summary message indi- cating whether the archive is OK or not: unzip -tq letters To test all zipfiles in the current directory, printing Info-ZIP 31 May 1997 (v5.31) 10 UNZIP(1L) UNZIP(1L) only the summaries: unzip -tq \*.zip (The backslash before the asterisk is only required if the shell expands wildcards, as in Unix; double quotes could have been used instead, as in the source examples below.) To extract to standard output all members of let- ters.zip whose names end in .tex, auto-converting to the local end-of-line convention and piping the output into more(1): unzip -ca letters \*.tex | more To extract the binary file paper1.dvi to standard output and pipe it to a printing program: unzip -p articles paper1.dvi | dvips To extract all FORTRAN and C source files--*.f, *.c, *.h, and Makefile--into the /tmp directory: unzip source.zip "*.[fch]" Makefile -d /tmp (the double quotes are necessary only in Unix and only if 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 local standard (without respect to any files that might be marked ``binary''): unzip -aaCL source.zip "*.[fch]" makefile -d /tmp To extract only newer versions of the files already in the current directory, without querying (NOTE: be careful of unzipping in one timezone 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 cur- rent directory and to create any files not already there (same caveat as previous example): unzip -uo sources To display a diagnostic screen showing which unzip and Info-ZIP 31 May 1997 (v5.31) 11 UNZIP(1L) UNZIP(1L) zipinfo options are stored in environment variables, whether decryption support was compiled 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 don't hurt) TIPS The current maintainer, being a lazy sort, finds it very useful to define 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 unzip will report ``No errors detected in compressed data of zipfile.zip,'' after which one may breathe a sigh of relief. The maintainer also finds it useful to set the UNZIP envi- ronment variable to ``-aL'' and is tempted to add ``-C'' as well. His ZIPINFO variable 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 processing completed successfully any- way. 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. Processing may have completed Info-ZIP 31 May 1997 (v5.31) 12 UNZIP(1L) UNZIP(1L) successfully anyway; some broken zipfiles created by other archivers have simple work- arounds. 3 a severe error in the zipfile format was detected. Processing probably failed imme- diately. 4 unzip was unable to allocate memory for one or more buffers during program initializa- tion. 5 unzip was unable to allocate memory or unable to obtain a tty to read the decryp- tion password(s). 6 unzip was unable to allocate memory during decompression to disk. 7 unzip was unable to allocate memory during in-memory decompression. 8 [currently not used] 9 the specified zipfiles were not found. 10 invalid options were specified on the com- mand 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 con- trol-C (or similar) 81 no files were found due to unsupported com- pression methods or unsupported decryption. (If even one additional file is successfully processed, however, the exit status is 1.) 82 no files were found due to bad decryption password(s). This is also the exit status if no files were found due to a combination of unsupported compression and bad pass- words. As in the previous case, however, a single successful file will result in an exit status of 1 instead.) VMS interprets standard Unix (or PC) return values as other, scarier-looking things, so unzip instead maps them Info-ZIP 31 May 1997 (v5.31) 13 UNZIP(1L) UNZIP(1L) into VMS-style status codes. The current mapping is as follows: 1 (success) for normal exit, 0x7fff0001 for warning errors, and (0x7fff000? + 16*nor- mal_unzip_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 expand upon this behavior: defining RETURN_CODES results in a human- readable explanation of what the error status means. BUGS Multi-part archives are not yet supported, except in con- junction with zip. (All parts must be concatenated together in order, and then ``zip -F'' must be performed on the concatenated archive in order to ``fix'' it.) 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 is overly simplistic in its handling of screen output; as noted above, it fails to detect the wrapping of long lines and may thereby cause lines at the top of the screen to be scrolled off before being read. unzip should detect and treat each occurrence of line-wrap as one additional line printed. This requires knowledge of the screen's width as well as its height. In addition, unzip should detect the true screen geometry on all systems. Dates, times and permissions of stored directories are not restored except under Unix. [MS-DOS] When extracting or testing files from an archive on a defective floppy diskette, if the ``Fail'' option is chosen from DOS's ``Abort, Retry, Fail?'' message, older versions of unzip may hang the system, requiring a reboot. This problem appears to be fixed, but control-C (or con- trol-Break) can still be used to terminate unzip. Under DEC Ultrix, unzip would sometimes fail on long zip- files (bad CRC, not always reproducible). This was appar- ently due either to a hardware bug (cache memory) or an operating system bug (improper handling of page faults?). Since Ultrix has been abandoned in favor of Digital Unix (OSF/1), this may not be an issue anymore. [Unix] Unix special files such as FIFO buffers (named Info-ZIP 31 May 1997 (v5.31) 14 UNZIP(1L) UNZIP(1L) pipes), block devices and character devices are not restored even if they are somehow represented in the zip- file, nor are hard-linked files relinked. Basically the only file types restored by unzip are regular files, directories and symbolic (soft) links. [OS/2] Extended attributes for existing directories are only updated if the -o (``overwrite all'') option is given. This is a limitation of the operating system; because directories only have a creation time associated with them, unzip has no way to determine whether the stored attributes are newer or older than those on disk. In practice this may mean a two-pass approach is required: first unpack the archive normally (with or without fresh- ening/updating existing files), then overwrite just the directory entries (e.g., ``unzip -o foo */''). [VMS] When extracting to another directory, only the [.foo] syntax is accepted for the -d option; the simple Unix foo syntax is silently ignored (as is the less common VMS foo.dir syntax). [VMS] When the file being extracted already exists, unzip's query only allows skipping, overwriting or renam- ing; there should additionally be a choice for creating a new version of the file. In fact, the ``overwrite'' choice does create a new version; the old version is not overwritten or deleted. SEE ALSO funzip(1L), zip(1L), zipcloak(1L), zipgrep(1L), zip- info(1L), zipnote(1L), zipsplit(1L) URL The Info-ZIP home page is currently at http://www.cdrom.com/pub/infozip/ . AUTHORS The primary Info-ZIP authors (current semi-active members of the Zip-Bugs workgroup) are: Greg ``Cave Newt'' Roelofs (UnZip); Onno van der Linden (Zip); Jean-loup Gailly (compression); Mark Adler (decompression, fUnZip); Christian Spieler (VMS, MS-DOS, Windows 95, NT, shared code, general Zip and UnZip integration and optimization); Mike White (Windows GUI, Windows DLLs); Kai Uwe Rommel (OS/2); Paul Kienitz (Amiga, Windows 95); Chris Herborth (BeOS, QNX, Atari); Jonathan Hudson (SMS/QDOS); Karl Davis and Sergio Monesi (Acorn RISC OS); Harald Denker (Atari, MVS); John Bush (Solaris, Amiga); Hunter Goatley (VMS); Steve Salisbury (Windows 95, NT); Steve Miller (Windows CE GUI), Johnny Lee (MS-DOS, Windows 95, NT); and Robert Heath (Windows GUI). The author of the original unzip code upon which Info-ZIP's was based is Samuel H. Smith; Carl Mascott did the first Unix port; and David P. Info-ZIP 31 May 1997 (v5.31) 15 UNZIP(1L) UNZIP(1L) Kirschbaum organized and led Info-ZIP in its early days with Keith Petersen hosting the original mailing list at WSMR-SimTel20. The full list of contributors to UnZip has grown quite large; please refer to the CONTRIBS file in the UnZip source distribution for a relatively complete version. VERSIONS v1.2 15 Mar 89 Samuel H. Smith v2.0 9 Sep 89 Samuel H. Smith v2.x fall 1989 many Usenet contributors v3.0 1 May 90 Info-ZIP (DPK, consolidator) v3.1 15 Aug 90 Info-ZIP (DPK, consolidator) v4.0 1 Dec 90 Info-ZIP (GRR, maintainer) v4.1 12 May 91 Info-ZIP v4.2 20 Mar 92 Info-ZIP (Zip-Bugs subgroup, GRR) v5.0 21 Aug 92 Info-ZIP (Zip-Bugs subgroup, GRR) v5.01 15 Jan 93 Info-ZIP (Zip-Bugs subgroup, GRR) v5.1 7 Feb 94 Info-ZIP (Zip-Bugs subgroup, GRR) v5.11 2 Aug 94 Info-ZIP (Zip-Bugs subgroup, GRR) v5.12 28 Aug 94 Info-ZIP (Zip-Bugs subgroup, GRR) v5.2 30 Apr 96 Info-ZIP (Zip-Bugs subgroup, GRR) v5.3 22 Apr 97 Info-ZIP (Zip-Bugs subgroup, GRR) v5.31 31 May 97 Info-ZIP (Zip-Bugs subgroup, GRR) Info-ZIP 31 May 1997 (v5.31) 16