ZIP(1L)ZIP(1L)NAME
zip, 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 compress(1) and is compatible with PKZIP (Phil
Katz’s ZIP for MSDOS systems).
A companion program (unzip(1L)), unpacks zip archives.
The zip and unzip(1L) programs can work with archives pro‐
duced by PKZIP, and PKZIP and PKUNZIP can work with
archives produced by zip. zip version 2.3 is compatible
with PKZIP 2.04. Note that PKUNZIP 1.10 cannot extract
files produced by PKZIP 2.04 or zip 2.3. 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 speci‐
fying 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 compressing unused files or directo‐
ries.
The zip program puts one or more compressed files into a
single zip archive, 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
archive with a single command. Compression ratios of 2:1
to 3:1 are common for text files. zip has one compression
method (deflation) and can also store files without com‐
pression. 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 identically named entries in the zip archive or
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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 con‐
junction 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 compressed, 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 pur‐
pose 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 termi‐
nal, zip acts as a filter, compressing standard input to
standard output. For example,
tar cf ‐ . | zip | dd of=/dev/nrst0 obs=16k
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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 exten‐
sion, the extension .zip is added. If the name already
contains an extension other than .zip the existing exten‐
sion is kept unchanged.
OPTIONS
‐a [Systems using EBCDIC] Translate file to ASCII for‐
mat.
‐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
"preamble" 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 unstruc‐
tured files
‐b path
Use the specified path for the temporary zipInfo‐ZIP 14 August 1999 (v2.3) 3
ZIP(1L)ZIP(1L)
archive. For example:
zip ‐b /tmp stuff *
will put the temporary zip archive in the directory
/tmp, copying over stuff.zip to the current direc‐
tory 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 opera‐
tions (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 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 direc‐
tories. 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
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latter cannot be set as default in the ZIPOPT envi‐
ronment 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 filename.
‐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 archives 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 cor‐
rectly.
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 auto‐
matic 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 signatures to identify the limits
between the archive members. The single ‐F is more
reliable if the archive is not too much damaged,
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
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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
archive 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 archive 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 substitution, so that the name
matching is performed by zip at all directory lev‐
els.
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 archives when SparkFS is
loaded) as directories but will store them as sin‐
gle files.
For example, if you have SparkFS loaded, zipping a
Spark archive will result in a zipfile containing a
directory (and its content) while using the ’I’
option will result in a zipfile containing a Spark
archive. Obviously this second case will also be
obtained (without the ’I’ option) if SparkFS isn’t
loaded.
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‐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 convention 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 ensure that
unzip ‐a on Unix will get back an exact copy of the
original file, to undo the effect of zip ‐l.
‐ll Translate the MSDOS end‐of‐line CR LF into Unix LF.
This option should not be used on binary files.
This option can be used on MSDOS if the zip file is
intended for unzip under Unix.
‐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 direc‐
tory 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
semicolons. For example:
Info‐ZIP 14 August 1999 (v2.3) 7
ZIP(1L)ZIP(1L)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 spe‐
cialized compression methods). By default, zip
does not compress 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 comments. 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 INSECURE! Many multi‐user operating sys‐
tems 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
Info‐ZIP 14 August 1999 (v2.3) 8
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even worse. Whenever possible, use the non‐echo‐
ing, 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 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 sub‐
stitution 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 (probably not what was intended).
‐R Travel the directory structure recursively starting
at the current 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 otherwise.
‐t mmddyyyy
Do not operate on files modified prior to the
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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 subdirecto‐
ries 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 subdirecto‐
ries 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 oddities.
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When ‐v is the only command line argument, and std‐
out 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 dis‐
tribution 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. zip archives cre‐
ated with this option 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 excluding all the files that end in .o. The
backslash avoids the shell filename substitution,
so that the name matching is performed by zip at
all directory levels.
Also possible:
zip ‐r foo foo ‐x@exclude.lst
which will include the contents of foo in foo.zip
while excluding all the files that match the pat‐
terns in the file exclude.lst.
‐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 compressing 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
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‐# Regulate the speed of compression using the speci‐
fied digit #, where ‐0 indicates no compression
(store all files), ‐1 indicates the fastest com‐
pression method (less compression) and ‐9 indicates
the slowest compression method (optimal compres‐
sion, ignores the suffix list). The default com‐
pression 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 filename per line.
‐$ [MSDOS, OS/2, WIN32] Include the volume label for
the the drive holding the first file to be com‐
pressed. 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 suffixes).
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 directory.
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:
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ZIP(1L)ZIP(1L)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 corre‐
sponding compressed zip archive. 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. Watch this space for
details on MSDOS and VMS operation.
The UNIX shells (sh(1) and csh(1)) do filename substitu‐
tion 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 pat‐
tern, 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 char‐
acters 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
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path prefix is. Note that the backslash must precede
every special character (i.e. ?*[]), or the entire argu‐
ment 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 speci‐
fied 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. Processing may have completed
successfully anyway; some broken 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. Processing probably failed imme‐
diately.
6 entry too large to be split with zipsplit
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ZIP(1L)ZIP(1L)
7 invalid comment format
8 zip ‐T failed or out of memory
9 the user aborted zip prematurely with con‐
trol‐C (or similar)
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 2.3 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 2.3 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 transfer
zip files from Vax to MSDOS, type "set file type block" on
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ZIP(1L)ZIP(1L)
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 DEC‐
net syntax foo::*.*.
On OS/2, zip cannot match some names, such as those
including an exclamation 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 DosQueryPathInfo(). 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. Therefore the value reported by
zip (which uses this 32‐bit‐mode size) differs from that
reported by DIR. zip stores the 32‐bit format for porta‐
bility, even the 16‐bit MS‐C‐compiled version running on
OS/2 1.3, so even this one shows the 32‐bit‐mode size.
AUTHORS
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 origi‐
nal 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 by email to:
zip‐bugs@lists.wku.edu. 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 format, and .ZIP filename
extension, and for accepting minor changes to the file
Info‐ZIP 14 August 1999 (v2.3) 16
ZIP(1L)ZIP(1L)
format; to Steve Burg for clarifications on the deflate
format; to Haruhiko Okumura and Leonid Broukhis for pro‐
viding 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 possible. 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 14 August 1999 (v2.3) 17
