zip [-cdDfFghjklLmoqrSTuvVwyz@] [-b path] [-n suffixes]
[-t mmddyy] [zipfile [file1 file2 ...]] [-xi list]
The zip(1) utility is a compression and file packaging utility for many different operating systems, including Interix. It is analogous to a combination of the Interix utilities tar(1) and compress(1) and is compatible with PKZIP (Phil Katz's ZIP for MS-DOS systems).
The companion program unzip(1) unpacks zip(1) archives. The zip(1) and unzip(1) programs can work with archives produced by PKZIP, and PKZIP and PKUNZIP can work with archives produced by zip(1). The zip(1) utility version 2.0.1 is compatible with PKZIP 2.04. Note that PKUNZIP 1.10 cannot extract files produced by PKZIP 2.04 or zip(1) 2.0.1. You must use PKUNZIP 2.04g or unzip(1) 5.0p1 (or later versions) to extract them.
For a brief help on zip(1) and unzip(1), run each without specifying any parameters on the command line.
The program is useful for packaging a set of files for distribution, archiving files, and saving disk space by temporarily compressing unused files or directories.
The zip(1) utility accepts the following options:
zip -b /tmp stuff *
will put the temporary zip(1) archive in the directory
/tmp, copying over stuff.zip to the current directory
when done. This option is useful only when updating an existing
archive and if the file system containing this old archive does not
have enough space to hold both old and new archive at the same
time.
zip -d cat cat/tom/junk cat/harry/\* \*.o
will remove the entry cat/tom/junk, all of the files that
start with cat/harry/, and all of the files that end with
.o (in any path). Note that shell path name expansion has
been inhibited with backslashes, so that zip(1) can see the
asterisks, enabling zip(1) to match on the contents of the
zip(1) archive instead of the contents of the current
directory.
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.
zip -f cat
This command should be run from the same directory from which the
original zip(1) command was run, since paths stored in
zip(1) archives are always relative.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 binary. After the repair, the -t option of unzip(1) might show that some files have a bad cyclic redundancy check (CRC). Such files cannot be recovered; you can remove them from the archive using the -d option of zip(1).
zip -r cat . -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 -r cat *.c
PKZIP does not allow recursion in directories other than the
current one.) The backslash prevents the shell file-name
substitution, so that the name matching is performed by
zip(1) at all directory levels.
zip -rn .Z:.zip:.tiff:.gif:.snd cat cat
will copy everything from cat into cat.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(1) 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 Interix with csh:
setenv ZIPOPT "-n .gif:.zip"
To attempt compression on all files, use:
zip -n : cat
The maximum compression option -9 also attempts compression on all files regardless of extension.
zip -o cat
will change the last modified time of cat.zip to the latest
time of the entries in cat.zip.
zip -r cat cat
In this case, all the files and directories in cat are saved
in a zip(1) archive named cat.zip, including files
with names starting with ".", because the recursion does not use
the shell's file-name substitution mechanism. If you want to
include only a specific subset of the files in directory cat
and its subdirectories, use the -i option to the specify the
pattern of files to be included. You should not use -r with
the name ".*", because that matches "..", which will attempt to zip
up the parent directory (probably not what was intended).
zip -rt 120791 infamy cat
will add all the files in cat and its subdirectories that
were last modified on or after 7 December 1991, to the
zip(1) archive infamy.zip.
zip -u stuff *
will add any new files in the current directory, and update any
files that have been modified since the zip(1) archive
stuff.zip was last created/modified (note that zip(1)
will not try to pack stuff.zip into itself when you do
this).
zip -r cat cat -x \*.o
which will include the contents of cat in cat.zip
while excluding all the files that end in .o. The backslash
avoids the shell file name substitution, so that the name matching
is performed by zip(1) at all directory levels.The zip(1) program puts one or more compressed files into a single zip(1) archive, along with information about the files (name, path, date, time of last modification, and protection, and check information to verify file integrity). An entire directory structure can be packed into a zip(1) archive with a single command. Compression ratios of 2:1 to 3:1 are common for text files. The zip(1) utility has one compression method (deflation) and can also store files without compression. The zip(1) utility automatically chooses the better of the two for each file to be compressed.
When given the name of an existing zip(1) archive, zip(1) will replace identically named entries in the zip(1) archive or add entries for new names. For example, if cat.zip exists and contains cat/file1 and cat/file2, and the directory cat contains the files cat/file1 and cat/file3, then:
zip -r cat cat
will replace cat/file1 in cat.zip and add cat/file3 to cat.zip. After this, cat.zip contains cat/file1, cat/file2, and cat/file3, with cat/file2 unchanged from before.
If the file list is specified as -@, zip(1) takes the list of input files from standard input. Under Interix, 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). The zip(1) utility 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.
The zip(1) utility 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 purpose
of backing up the current directory. This generally produces better
compression than the previous example using the -r option,
because zip(1) 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(1) acts as a filter, compressing standard input to
standard output. For example:
tar cf - . | zip | dd of=/dev/nrst0 obs=16k
is equivalent to
tar cf - . | zip - - | dd of=/dev/nrst0 obs=16k
zip(1) archives created in this manner can be extracted with
the program gunzip(1), which is provided in the
gzip(1) package. For example:
dd if=/dev/nrst0 ibs=16k | gunzip | tar xvf -
When changing an existing zip(1) archive, zip(1) 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(1) 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.
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 file name 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 cat cat
creates the archive cat.zip, containing all the files and
directories in the directory cat that is contained within
the current directory.
You might want to make a zip(1) archive that contains the files in cat, without recording the directory name, cat. You can use the -j option to leave off the paths, as in:
zip -j cat cat/*
If you are short on disk space, you might not have enough room to hold both the original directory and the corresponding compressed zip(1) archive. In this case, you can create the archive in steps using the -m option. If cat contains the subdirectories tom, dick, and harry, you can:
zip -rm cat cat/tom
zip -rm cat cat/dick
zip -rm cat cat/harry
where the first command creates cat.zip, and the next two add to it. At the completion of each zip(1) command, the last created archive is deleted, making room for the next zip(1) command to function.
This section applies only to open and POSIX systems. Watch this space for details on MS-DOS and VMS operation.
The standard shells (sh(1) and ksh(1)) do file-name substitution on command arguments. The special characters are:
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(1) program can do the same matching on names that are in the zip(1) 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(1) 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(1) 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 (that is, ?*[]), or the entire argument must be enclosed in double quotes ("").
In general, use backslash to make zip(1) 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).
zip(1) 2.0.1 is not compatible with PKUNZIP 1.10. Use zip(1) 1.1 to produce zip(1) files which can be extracted by PKUNZIP 1.10.
The zip(1) files produced by zip(1) 2.0.1 must not be updated by zip(1) 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(1) 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(1) files are expected to work with zip(1). Others can be converted using Rahul Dhesi's BILF program. This version of zip(1) handles some of the conversion internally. When using Kermit to transfer zip files from Vax to MS-DOS, type "set file type block" on the Vax. When transferring from MS-DOS to Vax, type "set file type fixed" on the Vax. In both cases, type "set file type binary" on MS-DOS.
Under VMS, zip(1) hangs for file specification that uses DECnet syntax cat::*.*.
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 do not find such names. Other programs such as GNU tar are also affected by this bug.
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 is a linked list) to have all fields on four-byte boundaries for portability to future RISC OS/2 versions. Therefore the value reported by zip(1) (which uses this 32-bit-mode size) differs from that reported by DIR. The zip(1) utility 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.
Copyright (C) 1990-1993 Mark Adler, Richard B. Wales, Jean-loup Gailly, Kai Uwe Rommel, Igor Mandrichenko and John Bush. 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, 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@wkuvx1.bitnet For bug reports, please include the version of zip(1), the make options used to compile it, the computer and operating system in use, and as much additional information as possible.
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(1) file format, compression format, and .ZIP file name extension, and for accepting minor changes to the file format; to Steve Burg for clarifications on the deflate format; 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(1) 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 troff macros by R. P. C. Rodgers.
gzip(1)
tar(1)
unzip(1)