ZIP(1L)ZIP(1L)NAME
zip, zipcloak, zipnote, zipsplit - package and compress (archive) files
SYNOPSISzip [-aABcdDeEfFghjklLmoqrRSTuvVwXyz!@$] [-b path] [-n suffixes]
[-t mmddyyyy] [-tt mmddyyyy] [ zipfile [ file1 file2 ...]] [-xi list]
zipcloak [-dhL] [-b path] zipfile
zipnote [-hwL] [-b path] zipfile
zipsplit [-hiLpst] [-n size] [-b path] zipfile
DESCRIPTIONzip is a compression and file packaging utility for Unix, VMS, MSDOS,
OS/2, Windows NT, Minix, Atari and Macintosh, Amiga and Acorn RISC OS.
It is analogous to a combination of the UNIX commands tar(1) and com‐
press(1) and is compatible with PKZIP (Phil Katz's ZIP for MSDOS sys‐
tems).
A companion program (unzip(1L)), unpacks zip archives. The zip and
unzip(1L) programs can work with archives produced by PKZIP, and PKZIP
and PKUNZIP can work with archives produced by zip. zip version 2.31
is compatible with PKZIP 2.04. Note that PKUNZIP 1.10 cannot extract
files produced by PKZIP 2.04 or zip 2.31. You must use PKUNZIP 2.04g or
unzip 5.0p1 (or later versions) to extract them.
For a brief help on zip and unzip, run each without specifying any
parameters on the command line.
The program is useful for packaging a set of files for distribution;
for archiving files; and for saving disk space by temporarily compress‐
ing unused files or directories.
The zip program puts one or more compressed files into a single zip ar‐
chive, along with information about the files (name, path, date, time
of last modification, protection, and check information to verify file
integrity). An entire directory structure can be packed into a zip ar‐
chive with a single command. Compression ratios of 2:1 to 3:1 are com‐
mon for text files. zip has one compression method (deflation) and can
also store files without compression. zip automatically chooses the
better of the two for each file to be compressed.
When given the name of an existing zip archive, zip will replace iden‐
tically named entries in the zip archive or add entries for new names.
For example, if foo.zip exists and contains foo/file1 and foo/file2,
and the directory foo contains the files foo/file1 and foo/file3, then:
zip-r foo foo
will replace foo/file1 in foo.zip and add foo/file3 to foo.zip. After
this, foo.zip contains foo/file1, foo/file2, and foo/file3, with
foo/file2 unchanged from before.
If the file list is specified as -@, [Not on MacOS] zip takes the list
of input files from standard input. Under UNIX, this option can be
used to powerful effect in conjunction with the find(1) command. For
example, to archive all the C source files in the current directory and
its subdirectories:
find . -name "*.[ch]" -print | zip source -@
(note that the pattern must be quoted to keep the shell from expanding
it). zip will also accept a single dash ("-") as the zip file name, in
which case it will write the zip file to standard output, allowing the
output to be piped to another program. For example:
zip-r - . | dd of=/dev/nrst0 obs=16k
would write the zip output directly to a tape with the specified block
size for the purpose of backing up the current directory.
zip also accepts a single dash ("-") as the name of a file to be com‐
pressed, in which case it will read the file from standard input,
allowing zip to take input from another program. For example:
tar cf - . | zip backup -
would compress the output of the tar command for the purpose of backing
up the current directory. This generally produces better compression
than the previous example using the -r option, because zip can take
advantage of redundancy between files. The backup can be restored using
the command
unzip -p backup | tar xf -
When no zip file name is given and stdout is not a terminal, zip acts
as a filter, compressing standard input to standard output. For exam‐
ple,
tar cf - . | zip | dd of=/dev/nrst0 obs=16k
is equivalent to
tar cf - . | zip - - | dd of=/dev/nrst0 obs=16k
zip archives created in this manner can be extracted with the program
funzip which is provided in the unzip package, or by gunzip which is
provided in the gzip package. For example:
dd if=/dev/nrst0 ibs=16k | funzip | tar xvf -
When changing an existing zip archive, zip will write a temporary file
with the new contents, and only replace the old one when the process of
creating the new version has been completed without error.
If the name of the zip archive does not contain an extension, the
extension .zip is added. If the name already contains an extension
other than .zip the existing extension is kept unchanged.
OPTIONS-a [Systems using EBCDIC] Translate file to ASCII format.
-A Adjust self-extracting executable archive. A self-extracting
executable archive is created by prepending the SFX stub to an
existing archive. The -A option tells zip to adjust the entry
offsets stored in the archive to take into account this "pream‐
ble" data.
Note: self-extracting archives for the Amiga are a special case. At
present, only the Amiga port of Zip is capable of adjusting or updating
these without corrupting them. -J can be used to remove the SFX stub
if other updates need to be made.
-B [VM/CMS and MVS] force file to be read binary (default is text).
-Bn [TANDEM] set Edit/Enscribe formatting options with n defined as
bit 0: Don't add delimiter (Edit/Enscribe)
bit 1: Use LF rather than CR/LF as delimiter (Edit/Enscribe)
bit 2: Space fill record to maximum record length (Enscribe)
bit 3: Trim trailing space (Enscribe)
bit 8: Force 30K (Expand) large read for unstructured files
-b path
Use the specified path for the temporary zip archive. For exam‐
ple:
zip-b /tmp stuff *
will put the temporary zip archive in the directory /tmp, copy‐
ing over stuff.zip to the current directory when done. This
option is only useful when updating an existing archive, and the
file system containing this old archive does not have enough
space to hold both old and new archives at the same time.
-c Add one-line comments for each file. File operations (adding,
updating) are done first, and the user is then prompted for a
one-line comment for each file. Enter the comment followed by
return, or just return for no comment.
-d Remove (delete) entries from a zip archive. For example:
zip-d foo foo/tom/junk foo/harry/\* \*.o
will remove the entry foo/tom/junk, all of the files that start
with foo/harry/, and all of the files that end with .o (in any
path). Note that shell pathname expansion has been inhibited
with backslashes, so that zip can see the asterisks, enabling
zip to match on the contents of the zip archive instead of the
contents of the current directory.
Under systems where the shell does not expand wildcards, such as
MSDOS, the backslashes are not needed. The above would then be
zip-d foo foo/tom/junk foo/harry/* *.o
Under MSDOS, -d is case sensitive when it matches names in the
zip archive. This requires that file names be entered in upper
case if they were zipped by PKZIP on an MSDOS system.
-df [MacOS] Include only data-fork of files zipped into the archive.
Good for exporting files to foreign operating-systems.
Resource-forks will be ignored at all.
-D Do not create entries in the zip archive for directories.
Directory entries are created by default so that their
attributes can be saved in the zip archive. The environment
variable ZIPOPT can be used to change the default options. For
example under Unix with sh:
ZIPOPT="-D"; export ZIPOPT
(The variable ZIPOPT can be used for any option except -i and -x
and can include several options.) The option -D is a shorthand
for -x "*/" but the latter cannot be set as default in the
ZIPOPT environment variable.
-e Encrypt the contents of the zip archive using a password which
is entered on the terminal in response to a prompt (this will
not be echoed; if standard error is not a tty, zip will exit
with an error). The password prompt is repeated to save the
user from typing errors.
-E [OS/2] Use the .LONGNAME Extended Attribute (if found) as file‐
name.
-f Replace (freshen) an existing entry in the zip archive only if
it has been modified more recently than the version already in
the zip archive; unlike the update option (-u) this will not add
files that are not already in the zip archive. For example:
zip-f foo
This command should be run from the same directory from which
the original zip command was run, since paths stored in zip ar‐
chives are always relative.
Note that the timezone environment variable TZ should be set
according to the local timezone in order for the -f , -u and -o
options to work correctly.
The reasons behind this are somewhat subtle but have to do with
the differences between the Unix-format file times (always in
GMT) and most of the other operating systems (always local time)
and the necessity to compare the two. A typical TZ value is
``MET-1MEST'' (Middle European time with automatic adjustment
for ``summertime'' or Daylight Savings Time).
-F Fix the zip archive. This option can be used if some portions of
the archive are missing. It is not guaranteed to work, so you
MUST make a backup of the original archive first.
When doubled as in -FF the compressed sizes given inside the
damaged archive are not trusted and zip scans for special signa‐
tures to identify the limits between the archive members. The
single -F is more reliable if the archive is not too much dam‐
aged, for example if it has only been truncated, so try this
option first.
Neither option will recover archives that have been incorrectly
transferred in ascii mode instead of binary. After the repair,
the -t option of unzip may show that some files have a bad CRC.
Such files cannot be recovered; you can remove them from the ar‐
chive using the -d option of zip.
-g Grow (append to) the specified zip archive, instead of creating
a new one. If this operation fails, zip attempts to restore the
archive to its original state. If the restoration fails, the ar‐
chive might become corrupted. This option is ignored when
there's no existing archive or when at least one archive member
must be updated or deleted.
-h Display the zip help information (this also appears if zip is
run with no arguments).
-i files
Include only the specified files, as in:
zip-r foo . -i \*.c
which will include only the files that end in .c in the current
directory and its subdirectories. (Note for PKZIP users: the
equivalent command is
pkzip -rP foo *.c
PKZIP does not allow recursion in directories other than the
current one.) The backslash avoids the shell filename substitu‐
tion, so that the name matching is performed by zip at all
directory levels. Not escaping wildcards on shells that do
wildcard substitution before zip gets the command line may seem
to work but files in subdirectories matching the pattern will
never be checked and so not matched. For shells, such as Win32
command prompts, that do not replace file patterns containing
wildcards with the respective file names, zip will do the recur‐
sion and escaping the wildcards is not needed.
Also possible:
zip-r foo . -i@include.lst
which will only include the files in the current directory and
its subdirectories that match the patterns in the file
include.lst.
-I [Acorn RISC OS] Don't scan through Image files. When used, zip
will not consider Image files (eg. DOS partitions or Spark ar‐
chives when SparkFS is loaded) as directories but will store
them as single files.
For example, if you have SparkFS loaded, zipping a Spark archive
will result in a zipfile containing a directory (and its con‐
tent) while using the 'I' option will result in a zipfile con‐
taining a Spark archive. Obviously this second case will also be
obtained (without the 'I' option) if SparkFS isn't loaded.
-j Store just the name of a saved file (junk the path), and do not
store directory names. By default, zip will store the full path
(relative to the current path).
-jj [MacOS] record Fullpath (+ Volname). The complete path including
volume will be stored. By default the relative path will be
stored.
-J Strip any prepended data (e.g. a SFX stub) from the archive.
-k Attempt to convert the names and paths to conform to MSDOS,
store only the MSDOS attribute (just the user write attribute
from UNIX), and mark the entry as made under MSDOS (even though
it was not); for compatibility with PKUNZIP under MSDOS which
cannot handle certain names such as those with two dots.
-l Translate the Unix end-of-line character LF into the MSDOS con‐
vention CR LF. This option should not be used on binary files.
This option can be used on Unix if the zip file is intended for
PKUNZIP under MSDOS. If the input files already contain CR LF,
this option adds an extra CR. This ensures that unzip -a on Unix
will get back an exact copy of the original file, to undo the
effect of zip-l. See the note on binary detection for -ll
below.
-ll Translate the MSDOS end-of-line CR LF into Unix LF. This option
should not be used on binary files and a warning will be issued
when a file is converted that later is detected to be binary.
This option can be used on MSDOS if the zip file is intended for
unzip under Unix.
In Zip 2.31 binary detection has been changed from a simple per‐
centage of binary characters being considered binary to a more
selective method that should consider files in many character
sets, including UTF-8, that only include text characters in that
character set to be text. This allows unzip -a to convert these
files.
-L Display the zip license.
-m Move the specified files into the zip archive; actually, this
deletes the target directories/files after making the specified
zip archive. If a directory becomes empty after removal of the
files, the directory is also removed. No deletions are done
until zip has created the archive without error. This is useful
for conserving disk space, but is potentially dangerous so it is
recommended to use it in combination with -T to test the archive
before removing all input files.
-n suffixes
Do not attempt to compress files named with the given suffixes.
Such files are simply stored (0% compression) in the output zip
file, so that zip doesn't waste its time trying to compress
them. The suffixes are separated by either colons or semi‐
colons. For example:
zip-rn .Z:.zip:.tiff:.gif:.snd foo foo
will copy everything from foo into foo.zip, but will store any
files that end in .Z, .zip, .tiff, .gif, or .snd without trying
to compress them (image and sound files often have their own
specialized compression methods). By default, zip does not com‐
press files with extensions in the list
.Z:.zip:.zoo:.arc:.lzh:.arj. Such files are stored directly in
the output archive. The environment variable ZIPOPT can be used
to change the default options. For example under Unix with csh:
setenv ZIPOPT "-n .gif:.zip"
To attempt compression on all files, use:
zip-n : foo
The maximum compression option -9 also attempts compression on
all files regardless of extension.
On Acorn RISC OS systems the suffixes are actually filetypes (3
hex digit format). By default, zip does not compress files with
filetypes in the list DDC:D96:68E (i.e. Archives, CFS files and
PackDir files).
-N [Amiga, MacOS] Save Amiga or MacOS filenotes as zipfile com‐
ments. They can be restored by using the -N option of unzip. If
-c is used also, you are prompted for comments only for those
files that do not have filenotes.
-o Set the "last modified" time of the zip archive to the latest
(oldest) "last modified" time found among the entries in the zip
archive. This can be used without any other operations, if
desired. For example:
zip-o foo
will change the last modified time of foo.zip to the latest time
of the entries in foo.zip.
-P password
use password to encrypt zipfile entries (if any). THIS IS INSE‐
CURE! Many multi-user operating systems provide ways for any
user to see the 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 pass‐
words. (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 Quiet mode; eliminate informational messages and comment
prompts. (Useful, for example, in shell scripts and background
tasks).
-Qn [QDOS] store information about the file in the file header with
n defined as
bit 0: Don't add headers for any file
bit 1: Add headers for all files
bit 2: Don't wait for interactive key press on exit
-r Travel the directory structure recursively; for example:
zip-r foo foo
In this case, all the files and directories in foo are saved in
a zip archive named foo.zip, including files with names starting
with ".", since the recursion does not use the shell's file-name
substitution mechanism. If you wish to include only a specific
subset of the files in directory foo and its subdirectories, use
the -i option to specify the pattern of files to be included.
You should not use -r with the name ".*", since that matches
".." which will attempt to zip up the parent directory (proba‐
bly not what was intended).
-R Travel the directory structure recursively starting at the cur‐
rent directory; for example:
zip-R foo '*.c'
In this case, all the files matching *.c in the tree starting at
the current directory are stored into a zip archive named
foo.zip. Note for PKZIP users: the equivalent command is
pkzip -rP foo *.c
-S [MSDOS, OS/2, WIN32 and ATARI] Include system and hidden files.
[MacOS] Includes finder invisible files, which are ignored oth‐
erwise.
-t mmddyyyy
Do not operate on files modified prior to the specified date,
where mm is the month (0-12), dd is the day of the month (1-31),
and yyyy is the year. The ISO 8601 date format yyyy-mm-dd is
also accepted. For example:
zip-rt 12071991 infamy foo
zip-rt 1991-12-07 infamy foo
will add all the files in foo and its subdirectories that were
last modified on or after 7 December 1991, to the zip archive
infamy.zip.
-tt mmddyyyy
Do not operate on files modified after or at the specified date,
where mm is the month (0-12), dd is the day of the month (1-31),
and yyyy is the year. The ISO 8601 date format yyyy-mm-dd is
also accepted. For example:
zip-rtt 11301995 infamy foo
zip-rtt 1995-11-30 infamy foo
will add all the files in foo and its subdirectories that were
last modified before the 30 November 1995, to the zip archive
infamy.zip.
-T Test the integrity of the new zip file. If the check fails, the
old zip file is unchanged and (with the -m option) no input
files are removed.
-u Replace (update) an existing entry in the zip archive only if it
has been modified more recently than the version already in the
zip archive. For example:
zip-u stuff *
will add any new files in the current directory, and update any
files which have been modified since the zip archive stuff.zip
was last created/modified (note that zip will not try to pack
stuff.zip into itself when you do this).
Note that the -u option with no arguments acts like the -f
(freshen) option.
-v Verbose mode or print diagnostic version info.
Normally, when applied to real operations, this option enables
the display of a progress indicator during compression and
requests verbose diagnostic info about zipfile structure oddi‐
ties.
When -v is the only command line argument, and either stdin or
stdout is not redirected to a file, a diagnostic screen is
printed. In addition to the help screen header with program
name, version, and release date, some pointers to the Info-ZIP
home and distribution sites are given. Then, it shows informa‐
tion about the target environment (compiler type and version, OS
version, compilation date and the enabled optional features used
to create the zip executable.
-V [VMS] Save VMS file attributes and use portable form. zip ar‐
chives created with this option are truncated at EOF but still
may not be usable on other systems depending on the file types
being zipped.
-VV [VMS] Save VMS file attributes. zip archives created with this
option include the entire file and should be able to recreate
most VMS files on VMS systems but these archives will generally
not be usable on other systems.
-w [VMS] Append the version number of the files to the name,
including multiple versions of files. (default: use only the
most recent version of a specified file).
-x files
Explicitly exclude the specified files, as in:
zip-r foo foo -x \*.o
which will include the contents of foo in foo.zip while exclud‐
ing all the files that end in .o. The backslash avoids the
shell filename substitution, so that the name matching is per‐
formed by zip at all directory levels. If you do not escape
wildcards in patterns it may seem to work but files in subdirec‐
tories will not be checked for matches.
Also possible:
zip-r foo foo -x@exclude.lst
which will include the contents of foo in foo.zip while exclud‐
ing all the files that match the patterns in the file
exclude.lst (each file pattern on a separate line).
-X Do not save extra file attributes (Extended Attributes on OS/2,
uid/gid and file times on Unix).
-y Store symbolic links as such in the zip archive, instead of com‐
pressing and storing the file referred to by the link (UNIX
only).
-z Prompt for a multi-line comment for the entire zip archive. The
comment is ended by a line containing just a period, or an end
of file condition (^D on UNIX, ^Z on MSDOS, OS/2, and VAX/VMS).
The comment can be taken from a file:
zip-z foo < foowhat
-# Regulate the speed of compression using the specified digit #,
where -0 indicates no compression (store all files), -1 indi‐
cates the fastest compression method (less compression) and -9
indicates the slowest compression method (optimal compression,
ignores the suffix list). The default compression level is -6.
-! [WIN32] Use priviliges (if granted) to obtain all aspects of
WinNT security.
-@ Take the list of input files from standard input. Only one file‐
name per line.
-$ [MSDOS, OS/2, WIN32] Include the volume label for the drive
holding the first file to be compressed. If you want to include
only the volume label or to force a specific drive, use the
drive name as first file name, as in:
zip -$ foo a: c:bar
EXAMPLES
The simplest example:
zip stuff *
creates the archive stuff.zip (assuming it does not exist) and puts all
the files in the current directory in it, in compressed form (the .zip
suffix is added automatically, unless that archive name given contains
a dot already; this allows the explicit specification of other suf‐
fixes).
Because of the way the shell does filename substitution, files starting
with "." are not included; to include these as well:
zip stuff .* *
Even this will not include any subdirectories from the current direc‐
tory.
To zip up an entire directory, the command:
zip-r foo foo
creates the archive foo.zip, containing all the files and directories
in the directory foo that is contained within the current directory.
You may want to make a zip archive that contains the files in foo,
without recording the directory name, foo. You can use the -j option
to leave off the paths, as in:
zip-j foo foo/*
If you are short on disk space, you might not have enough room to hold
both the original directory and the corresponding compressed zip ar‐
chive. In this case, you can create the archive in steps using the -m
option. If foo contains the subdirectories tom, dick, and harry, you
can:
zip-rm foo foo/tom
zip-rm foo foo/dick
zip-rm foo foo/harry
where the first command creates foo.zip, and the next two add to it.
At the completion of each zip command, the last created archive is
deleted, making room for the next zip command to function.
PATTERN MATCHING
This section applies only to UNIX, though the ?, *, and [] special
characters are implemented on other systems including MSDOS and Win32.
Watch this space for details on MSDOS and VMS operation.
The UNIX shells (sh(1) and csh(1)) do filename substitution on command
arguments. The special characters are:
? match any single character
* match any number of characters (including none)
[] match any character in the range indicated within the brackets
(example: [a-f], [0-9]).
When these characters are encountered (without being escaped with a
backslash or quotes), the shell will look for files relative to the
current path that match the pattern, and replace the argument with a
list of the names that matched.
The zip program can do the same matching on names that are in the zip
archive being modified or, in the case of the -x (exclude) or -i
(include) options, on the list of files to be operated on, by using
backslashes or quotes to tell the shell not to do the name expansion.
In general, when zip encounters a name in the list of files to do, it
first looks for the name in the file system. If it finds it, it then
adds it to the list of files to do. If it does not find it, it looks
for the name in the zip archive being modified (if it exists), using
the pattern matching characters described above, if present. For each
match, it will add that name to the list of files to be processed,
unless this name matches one given with the -x option, or does not
match any name given with the -i option.
The pattern matching includes the path, and so patterns like \*.o match
names that end in ".o", no matter what the path prefix is. Note that
the backslash must precede every special character (i.e. ?*[]), or the
entire argument must be enclosed in double quotes ("").
In general, use backslash to make zip do the pattern matching with the
-f (freshen) and -d (delete) options, and sometimes after the -x
(exclude) option when used with an appropriate operation (add, -u, -f,
or -d).
ENVIRONMENT
ZIPOPT contains default options that will be used when running zip
ZIP [Not on RISC OS and VMS] see ZIPOPT
Zip$Options
[RISC OS] see ZIPOPT
Zip$Exts
[RISC OS] contains extensions separated by a : that will cause
native filenames with one of the specified extensions to be
added to the zip file with basename and extension swapped. zip
ZIP_OPTS
[VMS] see ZIPOPT
SEE ALSOcompress(1), shar(1L), tar(1), unzip(1L), gzip(1L)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.
2 unexpected end of zip file.
3 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.
4 zip was unable to allocate memory for one or more buffers
during program initialization.
5 a severe error in the zipfile format was detected. Pro‐
cessing probably failed immediately.
6 entry too large to split (with zipsplit), read, or write
7 invalid comment format
8 zip-T failed or out of memory
9 the user aborted zip prematurely with control-C (or simi‐
lar)
10 zip encountered an error while using a temp file
11 read or seek error
12 zip has nothing to do
13 missing or empty zip file
14 error writing to a file
15 zip was unable to create a file to write to
16 bad command line parameters
18 zip could not open a specified file to read
VMS interprets standard Unix (or PC) return values as other, scarier-
looking things, so zip instead maps them into VMS-style status codes.
The current mapping is as follows: 1 (success) for normal exit,
and (0x7fff000? + 16*normal_zip_exit_status) for all errors, where the
`?' is 0 (warning) for zip value 12, 2 (error) for the zip values 3, 6,
7, 9, 13, 16, 18, and 4 (fatal error) for the remaining ones.
BUGSzip 2.31 is not compatible with PKUNZIP 1.10. Use zip 1.1 to produce
zip files which can be extracted by PKUNZIP 1.10.
zip files produced by zip 2.31 must not be updated by zip 1.1 or PKZIP
1.10, if they contain encrypted members or if they have been produced
in a pipe or on a non-seekable device. The old versions of zip or PKZIP
would create an archive with an incorrect format. The old versions can
list the contents of the zip file but cannot extract it anyway (because
of the new compression algorithm). If you do not use encryption and
use regular disk files, you do not have to care about this problem.
Under VMS, not all of the odd file formats are treated properly. Only
stream-LF format zip files are expected to work with zip. Others can
be converted using Rahul Dhesi's BILF program. This version of zip
handles some of the conversion internally. When using Kermit to trans‐
fer zip files from Vax to MSDOS, type "set file type block" on the Vax.
When transfering from MSDOS to Vax, type "set file type fixed" on the
Vax. In both cases, type "set file type binary" on MSDOS.
Under VMS, zip hangs for file specification that uses DECnet syntax
foo::*.*.
On OS/2, zip cannot match some names, such as those including an excla‐
mation mark or a hash sign. This is a bug in OS/2 itself: the 32-bit
DosFindFirst/Next don't find such names. Other programs such as GNU
tar are also affected by this bug.
Under OS/2, the amount of Extended Attributes displayed by DIR is (for
compatibility) the amount returned by the 16-bit version of DosQuery‐
PathInfo(). Otherwise OS/2 1.3 and 2.0 would report different EA sizes
when DIRing a file. However, the structure layout returned by the
32-bit DosQueryPathInfo() is a bit different, it uses extra padding
bytes and link pointers (it's a linked list) to have all fields on
4-byte boundaries for portability to future RISC OS/2 versions. There‐
fore the value reported by zip (which uses this 32-bit-mode size) dif‐
fers from that reported by DIR. zip stores the 32-bit format for
portability, even the 16-bit MS-C-compiled version running on OS/2 1.3,
so even this one shows the 32-bit-mode size.
Development of Zip 3.0 is underway. See that source distribution for
many new features and the latest bug fixes.
AUTHORS
Copyright (C) 1997-2005 Info-ZIP.
Copyright (C) 1990-1997 Mark Adler, Richard B. Wales, Jean-loup Gailly,
Onno van der Linden, Kai Uwe Rommel, Igor Mandrichenko, John Bush and
Paul Kienitz. Permission is granted to any individual or institution
to use, copy, or redistribute this software so long as all of the orig‐
inal files are included, that it is not sold for profit, and that this
copyright notice is retained.
LIKE ANYTHING ELSE THAT'S FREE, ZIP AND ITS ASSOCIATED UTILITIES ARE
PROVIDED AS IS AND COME WITH NO WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED. IN NO EVENT WILL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
DAMAGES RESULTING FROM THE USE OF THIS SOFTWARE.
Please send bug reports and comments to: zip-bugs at www.info-zip.org.
For bug reports, please include the version of zip (see zip -h), the
make options used to compile it (see zip -v), the machine and operating
system in use, and as much additional information as possible.
ACKNOWLEDGEMENTS
Thanks to R. P. Byrne for his Shrink.Pas program, which inspired this
project, and from which the shrink algorithm was stolen; to Phil Katz
for placing in the public domain the zip file format, compression for‐
mat, and .ZIP filename extension, and for accepting minor changes to
the file format; to Steve Burg for clarifications on the deflate for‐
mat; to Haruhiko Okumura and Leonid Broukhis for providing some useful
ideas for the compression algorithm; to Keith Petersen, Rich Wales,
Hunter Goatley and Mark Adler for providing a mailing list and ftp site
for the Info-ZIP group to use; and most importantly, to the Info-ZIP
group itself (listed in the file infozip.who) without whose tireless
testing and bug-fixing efforts a portable zip would not have been pos‐
sible. Finally we should thank (blame) the first Info-ZIP moderator,
David Kirschbaum, for getting us into this mess in the first place.
The manual page was rewritten for UNIX by R. P. C. Rodgers.
Info-ZIP 27 February 2005 (v2.31) ZIP(1L)
