ZIP(1) ZIP(1)
NAME
zip - package and compress (archive) files
SYNOPSIS
zip [ -cdeEfghjklmoqruwyz@ ]
[ -b temppath ] [ -n suffixes ] [ -t mmddyy ]
[ zipfile list ] [ -x list ]
DESCRIPTION
zip is a compression and file packaging utility for Unix,
VMS, MSDOS, OS/2, Windows NT, Minix, Atari and Macintosh.
It is analogous to a combination of tar and compress and
is compatible with PKZIP (Phil Katz ZIP) for MSDOS sys-
tems.
There is a companion to zip called unzip (of course) which
you should be able to find the same place you got zip. zip
and unzip can work with files produced by PKZIP under
MSDOS, and PKZIP and PKUNZIP can work with files produced
by zip.
zip version 1.9 is compatible with pkzip 1.93a. Note that
pkunzip 1.10 cannot extract files produced by pkzip 1.93a
or zip 1.9. You must use pkunzip 1.93a or unzip 5.0 to
extract them.
For a brief help on zip and unzip, run each without speci-
fying any parameters on the command line.
zip puts one or more compressed files into a single "zip
file" along with information about the files, including
the name, path if requested, date and time last modified,
protection, and check information to verify the fidelity
of each entry. zip can also be used as a filter, com-
pressing standard input to standard output. zip can pack
an entire directory structure in a zip file 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 compression. It automati-
cally chooses the better of the two for each file to be
compressed.
zip is useful for packaging a set of files to send to
someone or for distribution; for archiving or backing up
files; and for saving disk space by temporarily compress-
ing unused files or directories.
HOW TO USE ZIP
The simplest use of zip is as follows:
zip stuff *
This will create the file "stuff.zip" (assuming it does
not exist) and put all the files in the current directory
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in stuff.zip in a compressed form. The .zip suffix is
added automatically, unless that file name given contains
a dot already. This allows specifying suffixes other than
".zip".
Because of the way the shell does filename substitution,
files that start with a "." are not included. To include
those as well, you can:
zip stuff .* *
Even this will not include any subdirectories that are in
the current directory. To zip up an entire directory, the
command:
zip -r foo foo
will create the file "foo.zip" containing all the files
and directories in the directory "foo" that is in the cur-
rent directory. (The first "foo" denotes the zip file, the
second one denotes the directory.) The "r" option means
recurse through the directory structure. In this case,
all the files and directories in foo are zipped, including
the ones that start with a ".", since the recursion does
not use the shell's file-name substitution. You should
not use -r with the name ".*", since that matches ".."
which will attempt to zip up the parent direc-
tory--probably not what was intended.
You may want to make a zip file that contains the files in
foo, but not record the directory name, foo. You can use
the -j (junk path) option to leave off the path:
zip -j foo foo/*
The -y option (only under Unix) will store symbolic links
as such in the zip file, instead of compressing and stor-
ing the file referred to in the link.
You might be zipping to save disk space, in which case you
could:
zip -rm foo foo
where the "m" option means "move". This will delete foo
and its contents after making foo.zip. No deletions will
be done until the zip has completed with no errors. This
option is obviously more dangerous and should be used with
care.
If the zip file already exists, these commands will
replace existing or add new entries to the zip file. For
example, if you were really short on disk space, you might
not have enough room simultaneously to hold the directory
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ZIP(1) ZIP(1)
foo and the compressed foo.zip. In this case, you could
do it in steps. If foo contained the subdirectories tom,
dick, and harry, then you could:
zip -rm foo foo/tom
zip -rm foo foo/dick
zip -rm foo foo/harry
where the first command would create foo.zip, and the next
two would add to it. At the completion of each zip com-
mand, the directory just zipped would be deleted, making
room in which the next zip command could work.
zip will also accept a single dash ("-") as the zip file
name, in which case it will write the zip file to stdout,
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 zip file
from stdin, allowing zip to take input from another pro-
gram. 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
is equivalent to
tar cf - . | zip - - | dd of=/dev/nrst0
Zip archives created in this manner can be extracted with
the program funzip which is provided in the unzip package.
For example,
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dd if=/dev/nrst0 | funzip | tar xvf -
MODIFYING EXISTING ZIP FILES
When given the name of an existing zip file with the above
commands, zip will replace identically named entries in
the zip file 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.
When changing an existing zip file, zip will write a tem-
porary file with the new contents, and only replace the
old one when the zip has completed with no errors. You can
use the -b option to specify a different path (usually a
different device) to put the temporary file in. For exam-
ple:
zip -b /tmp stuff *
will put the temporary zip file and the temporary compres-
sion files in the directory "/tmp", copying over stuff.zip
in the current directory when done.
If you are only adding entries to a zip file, not replac-
ing, and the -g option is given, then zip grows (appends
to) the file instead of copying it. The danger of this is
that if the operation fails, the original zip file is cor-
rupted and lost.
There are two other ways to change or add entries in a zip
file that are restrictions of simple addition or replace-
ment. The first is -u (update) which will add new entries
to the zip file as before but will replace existing
entries only if the modified date of the file is more
recent than the date recorded for that name in the zip
file. For example:
zip -u stuff *
will add any new files in the current directory, and
update any changed files in the zip file stuff.zip. Note
that zip will not try to pack stuff.zip into itself when
you do this. zip will always exclude the zip file from
the files on which to be operated.
The second restriction is -f (freshen) which, like update,
will only replace entries with newer files; unlike update,
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ZIP(1) ZIP(1)
will not add files that are not already in the zip file.
For this option, you may want to simply freshen all of the
files that are in the specified zip file. To do this you
would simply:
zip -f foo
Note that the -f option with no arguments freshens all the
entries in the zip file. The same is true of -u, and
hence "zip -u foo" and "zip -f foo" both do the same
thing.
This command should be run from the same directory from
which the original zip command was run, since paths stored
in zip files are always relative.
Another restriction that can be used with adding, updat-
ing, or freshening is -t (time), which will not operate on
files modified earlier than the specified date. For exam-
ple:
zip -rt 120791 infamy foo
will add all the files in foo and its subdirectories that
were last modified on December 7, 1991, or later to the
zip file infamy.zip.
Also, files can be explicitly excluded using the -x
option:
zip -r foo foo -x \*.o
which will zip up the contents of foo into foo.zip but
exclude all the files that end in ".o". Here the back-
slash causes zip to match file names that were found when
foo was searched.
The last operation is -d (delete) which will remove
entries from a zip file. An example might be:
zip -d foo foo/tom/junk foo/harry/\* \*.o
which 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 once again, the
shell expansion has been inhibited with backslashes, so
that zip can see the asterisks. zip can then match on the
contents of the zip file instead of the contents of the
current directory.
Under MSDOS, -d is case sensitive when it matches names in
the zip file. This allows deleting names that were zipped
on other systems, but requires that the names be entered
in upper case if they were zipped on an MSDOS system, so
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that the names can be found in the zip file and deleted.
MORE OPTIONS
As mentioned before, zip will use the best of two methods:
deflate or store.
The option -0 will force zip to use store on all files.
For example:
zip -r0 foo foo
will zip up the directory foo into foo.zip using only
store.
The speed of deflation can also be controlled with options
-1 (fastest method but less compression) to -9 (best com-
pression but slower). The default value is -5. For exam-
ple:
zip -r8 foo foo
In nearly all cases, a file that is already compressed
cannot be compressed further by zip, or if it can, the
effect is minimal. The -n option prevents zip from trying
to compress files that have 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 com-
press them. The suffixes are separated by either colons
or semicolons. For example:
zip -rn ".Z:.zip:.tiff:.gif:.snd" foo foo
will put everything in foo into foo.zip, but will store
any files that end in .Z, .zip, .tiff, .gif, or .snd with-
out trying to compress them. (Image and sound files often
have their own specialized compression methods.) The
default suffix list is ".Z:.zip;.zoo:.arc:.lzh:.arj". The
environment variable ZIPOPT can be used to change this
default. For example under Unix with csh:
setenv ZIPOPT "-n .gif:.zip"
The variable ZIPOPT can be used for any option and can
include several options.
Under Unix and under OS/2 (if files from an HPFS are
stored), zip will store the full path (relative to the
current path) and name of the file (or just the name if -j
is specified) in the zip file along with the Unix
attributes, and it will mark the entry as made under Unix.
If the zip file is intended for PKUNZIP under MSDOS, then
the -k (Katz) option should be used to attempt to convert
the names and paths to conform to MSDOS, store only the
MSDOS attribute (just the user write attribute from Unix),
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and mark the entry as made under MSDOS (even though it
wasn't).
The -o (older) option will set the "last modified" time of
the zip file to the latest "last modified" time of the
entries in the zip file. 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 lat-
est time of the entries in foo.zip.
The -e and -c options operate on all files updated or
added to the zip file. Encryption (-e) will prompt for a
password on the terminal and will not echo the password as
it is typed (if stderr is not a TTY, zip will exit with an
error). New zip entries will be encrypted using that
password. For added peace of mind, you can use -ee, which
will prompt for the password twice, checking that the two
are the same before using it. The encryption code is dis-
tributed separately, so the -e option may not be available
in your version.
One-line comments can be added for each file with the -c
option. The zip file operations (adding or updating) will
be done first, and you will then be prompted for a one-
line comment for each file. You can then enter the com-
ment followed by return, or just return for no comment.
The -z option will prompt you for a multi-line comment for
the entire zip file. This option can be used by itself,
or in combination with other options. 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). Since -z reads the lines from stdin, you can
simply take the comment from a file:
zip -z foo < foowhat
The -q (quiet) option eliminates the informational mes-
sages and comment prompts while zip is operating. This
might be used in shell scripts, for example, or if the zip
operation is being performed as a background task ("zip -q
foo *.c &").
zip can take a list of file names to operate on from stdin
using the -@ option. In Unix, this option can be used
with the find command to extend greatly the functionality
of zip. For example, to zip up all the C source files in
the current directory and its subdirectories, you can:
find . -type f -name "*.[ch]" -print | zip source -@
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Note that the pattern must be quoted to keep the shell
from expanding it.
Under VMS only, the -w option will append the version num-
ber of the files to the name and zip up multiple versions
of files. Without -w, zip will only use the most recent
version of the specified file(s).
The -l option translates 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".
If zip is run with the -h option, or with no arguments and
standard output is a terminal, the license and the com-
mand-argument and option help is shown. The -L option
just shows the license.
ABOUT PATTERN MATCHING
(Note: this section applies to Unix. Watch this space for
details on MSDOS and VMS operation.)
The Unix shell (sh or csh) does filename substitution on
command arguments. The special characters are ?, which
matches any single character; * which matches any number
of characters (including none); and [] which matches any
character in the range inside the brackets (like [a-f] or
[0-9]). When these characters are encountered (and not
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.
zip can do the same matching on names that are in the zip
file being modified or, in the case of the -x (exclude)
option, 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 will look for
the name in the zip file being modified (if it exists),
using the pattern matching characters above, if any. For
each match, it will add that name to the list of files to
do. After -x (exclude), the names are removed from the
to-do list instead of added.
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
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every special character (i.e. ?*[]), or the entire argu-
ment must be enclosed in double quotes ("").
In general, using backslash to make zip do the pattern
matching is used with the -f (freshen) and -d (delete)
options, and sometimes after the -x (exclude) option when
used with any operation (add, -u, -f, or -d). zip will
never use pattern matching to search the file system. If
zip has recursed into a directory, all files (and all
directories) in there are fair game.
COPYRIGHT
Copyright (C) 1990-1992 Mark Adler, Richard B. Wales,
Jean-loup Gailly, Kai Uwe Rommel and Igor Mandrichenko.
Permission is granted to any individual or institution to
use, copy, or redistribute this software so long as all of
the original files are included unmodified, that it is not
sold for profit, and that this copyright notice is
retained.
ACKNOWLEDGEMENTS
Thanks to R. P. Byrne for his Shrink.Pas program which
inspired this project; to Phil Katz for making the zip
file format, compression format, and .zip filename exten-
sion all public domain; to Steve Burg and Phil Katz for
help on unclear points of the deflate format; to Keith
Petersen and Rich Wales for providing a mailing list and
ftp site for the INFO-ZIP group to use; and most impor-
tantly, 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 INFO-ZIP moderator,
David Kirschbaum for getting us into this mess in the
first place.
SEE ALSO
unzip(1), tar(1), compress(1)
BUGS
WARNING: zip files produced by zip 1.9 must not be
*updated* by zip 1.0 or pkzip 1.10 or pkzip 1.93a, 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 destroy the zip structure. The old ver-
sions can list the contents of the zip file but cannot
extract it anyway (because of the new compression algo-
rithm). If you do not use encryption and use regular disk
files, you do not have to care about this problem.
zip 1.9 is compatible with pkzip 1.93a, except when two
features are used: encryption or zip file created in a
pipe or on a non seekable device. pkzip versions above 2.0
will support such files, and unzip 5.0 already supports
them.
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Without -y, when zip must compress a symbolic link to an
non existing file, it only displays a warning "name not
matched". A better warnign should be given.
Under VMS, not all of the odd file formats are treated
properly. Only zip files of format stream-LF and fixed
length 512 are expected to work with zip. Others can be
converted using Rahul Dhesi's BILF program. This version
of zip does handle some of the conversion internally.
When using Kermit to transfer 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 DEC-
net syntax (foo::*.*).
Under OS/2, the amount of External 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.
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.
That having been said, please send any problems or com-
ments via email to the Internet address
zip-bugs@cs.ucla.edu. For bug reports, please include the
version of zip, the make options you used to compile it,
the machine and operating system you are using, and as
much additional information as possible. Thank you for
your support.
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