Category : Windows NT Files
Archive   : NTZIP2.ZIP
Filename : ZIP.DOC

ZIP(1) UNIX Programmer's Manual ZIP(1)



NAME
zip - package and compress (archive) files

SYNOPSIS
zip [ -cdefghijklmnoqrsuwyz ] [ -b path ] [ -t mmddyy ] zip-
file list [ -x list ]

DESCRIPTION
Zip is a compression and file packaging utility for Unix,
MSDOS, OS/2, and VMS. It is analogous to a combination of
tar and compress and is compatible with PKZIP (Phil Katz
ZIP) for MSDOS systems.

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 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, pro-
tection, and check information to verify the fidelity of
each entry. 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 two compression
methods, implosion and shrinking, and automatically chooses
the better of the two for each file to be compressed.

Zip is useful for packaging a set of files to send to some-
one or for distribution; for archiving or backing up files;
and for saving disk space by temporarily compressing unused
files or directories.

HOW TO INSTALL ZIP
Zip is distributed as C source code that can be compiled on
a wide range of Unix machines, VAXes running VMS, and MSDOS
machines using Microsoft or Borland C++, and OS/2 machines
using Microsoft C. You will need Unzip (under Unix, MSDOS,
or VMS) or PKUNZIP (under MSDOS) to unpack the distribution
file, zip10.zip.

First, unpack the source as follows, assuming that you have
zip10.zip in the current directory:

mkdir zipsrc
cd zipsrc
unzip ../zip10

This extracts all source files and documentation in the
directory called "zipsrc". You then do:


make system

where "system" is one of: bsd, bsdold, sysv, next, next10,
sun, hpux, dnix, cray, 3b1, zilog, aux, convex, aix, or
minix. If you are using a NeXT running version 2.0 or
greater, then make next. If you are using 1.0, then make
next10. If you are using Sun OS 4.x, then make sun. If you
are using HPUX, then make hpux. The other special systems
are DNIX 5.2 or 5.3, Cray Unicos, AT&T 3B1 (also known as
Unix PC or PC 7300), Zilog Zeus, A/UX, Convex, AIX, and
MINIX. Otherwise, if you are using BSD Unix, try bsd. If
the linker cannot find _memset or _memcpy, try bsdold. If
you are using System V Unix or SCO Unix, try sysv. Also use
sysv on a Silicon Graphics (SGI) machine. You can also
cross-compile Zip for MSDOS under SCO 386 Unix using "make
scodos".

If none of these compiles, links, and functions properly on
your Unix system, see the section BUGS below for how to get
help.

If the appropriate system was selected, then the executable
"zip" will be created. You can move the executable "zip" to
an appropriate directory in the search path using a command
like:

mv zip ~/bin

or

mv zip /usr/local/bin

You can use the command "set" to see the current search
path. If you are using the C-Shell (csh), enter the com-
mand:

rehash

so csh can find the new command in the path. You are now
ready to use Zip.

You can also move the manual page (the raw form of what
you're reading) to where the Unix man command can find it
(assuming you have the necessary privileges):

mv zip.1 /usr/man/man1

You can get rid of the now unnecessary source and object
files with:

cd ..
rm -r zipsrc

This will remove the directory zip and its contents created
by unzip. You should keep the zip10.zip file around though,
in case you need to build it again or want to give it to a
colleague.

The steps for installation under MSDOS, OS/2, and VMS are
similar to the above: first unzip the distribution files
into their own directory. Then under MSDOS do one of:

make makefile.msc
make -fmakefile.bor


for Microsoft or Borland C++, respectively. Under OS/2:

nmake -f makefile.os2

for Microsoft C 6.00. Under VAX VMS:


@makevms

The installation process will also compile and link several
other utilities. They are zipcloak for encrypting and
decrypting zip files, zipnote for editing zip file comments,
zipsplit for splitting a zip file into several zip files,
and ship for sending zip files or any other binary file via
electronic mail. For command help on any of the zip* utili-
ties, simply enter the name with no arguments. For help
with ship, enter "ship -h".

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 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 current
directory. The "r" option means recurse through the direc-
tory 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 sub-
stitution. 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.

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 storing 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 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 command,
the directory just zipped would be deleted, making room in
which the next Zip command could work.

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. Also, the
two methods, shrink and implode, create temporary files that
are deleted after each file is zipped. You can use the -b
option to specify a different path (usually a different dev-
ice) to put the temporary files in. For example:

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 replacing,
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 corrupted 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 exam-
ple:

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,
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, updating,
or freshening is -t (time), which will not operate on files
modified earlier than the specified date. For example:

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 backslash
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 direc-
tory.

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 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:
shrink or implode. Usually implode is better, but sometimes
shrink is better, especially for smaller files. Sometimes
neither method produces a packed version smaller than the
original file, in which case it is stored in the zip file
with no compression (called the "store" method).

The option -s (shrink) will force Zip always to use shrink
or store, and the -i (implode) option forces Zip to use
implode or store. Shrinking is faster than imploding, and
so -s might be used when speed is more important than
optimal compression. Implode only (-i) might be used when
the unzipper for which the zip file is destined can only
handle implosion. An example of this is the PKSFXjr program
that comes with PKZIP. Also, -i is slightly faster than
imploding and shrinking at the same time. For example:

zip -rs foo foo

will zip up the directory foo into foo.zip using only shrink
or store. The speed of implosion can also be controlled
with options -0 (fastest method but less compression) to -9
(best compression but slower). The default value is -5. For
example:

zip -r0 foo foo

In nearly all cases, a file that is already compressed can-
not 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 suffixes: .Z, .zip, .zoo, or
.arc. Such files are simply stored (0% compression) in the
output zip file, so that Zip doesn't waste its time trying
to compress them. If the environment variable NOZIP is set,
then the suffixes listed there are used instead of the
default list. The suffixes are separated by either colons
or semicolons. For example, in Unix csh:

setenv NOZIP .Z:.zip:.tiff:.gif:.snd
zip -rn foo foo

will put everything in 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.) If the environ-
ment variable NOZIP exists but is empty or contains just a
colon or semicolon, then zip -n will store all the entries
and do no compression.

Under Unix and under OS/2 (if files from a 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), 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 latest
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.

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 comment fol-
lowed 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 messages
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 -

Note that the pattern must be quoted to keep the shell from
expanding it.

Under VMS only, the -w option will append the version number
of the files to the name and zip up multiple versions of
files. Without -w, Zip will only use the most recent ver-
sion of the specified file(s).

If Zip is run with no arguments or with the -h option, the
license and the command-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 char-
acter 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 pattern,
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 every spe-
cial character (i.e. ?*[]), or the entire argument 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 direc-
tories) in there are fair game.

COPYRIGHT
Copyright (C) 1990,1991 Mark Adler, Richard B. Wales, and
Jean-loup Gailly. 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 unmodi-
fied, that it is not sold for profit, and that this copy-
right notice is retained.

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 making the zip file format,
compression format, and .ZIP filename extension all public
domain; to Keith Petersen 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
Versions of PKUNZIP before 1.1 have a bug that on rare occa-
sions will prevent it from unzipping files produced by Zip
or PKZIP 1.1. If you experience such problems, we recommend
that you get PKUNZIP 1.1 or the portable Unzip, neither of
which have this problem.

Under MSDOS, Zip will find hidden and system files, but not
set the attributes appropriately in the zip file so that
Unzip can restore them. This will be fixed in the next
version.

Under VMS, not all of the odd file formats are treated prop-
erly. Only stream-LF format zip files are expected to work
with Zip. Others can be converted using Rahul Dhesi's BILF
program. The next version of Zip will handle some of the
conversion internally.

LIKE ANYTHING ELSE THAT'S FREE, ZIP AND ITS ASSOCIATED UTIL-
ITIES 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 comments
via email to the Internet address [email protected]. 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.