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Introduction

Working with zip and unzip represents some challenges for Unix admins who get used to gzip and other Unix style utilities, as those two originated in DOS which ahs different conventions then Unix and those conventions are still preserved in parameters.

To zip the current directory (zip file should be put into other directory recursively (the whole tree) use

zip -r f:\public_html.zip  * 

To zip the whole directory you can also specify it explicitly:

zip -r f:\public_html.zip  c:\public_html 

Typical Usage

For example, if you want to unzip many ZIP archives in a directory, the command:

unzip *.zip

doesn't work. To fix this situation you need to put the pattern in single quotes:

unzip '*.zip'

Or you can create an alias unzipall that will use Unix conventions. For example

alias unzipall='ls *.zip | xargs -l unzip'

You could also use a loop to unzip each file:

for x in /path/to/archives/*.zip; do unzip "$x"; done

or:

for x in $(ls /path/to/archives/*.zip 2>/dev/null); do unzip $x; done

Unlike many Unix commands (e.g., gzip and bzip2), the last argument to unzip isn't an arbitrarily long list of files. To process the command

unzip *.zip 

the shell expands the wildcard, so (assuming you have files named zipfile1.zip to zipfile4.zip) to

unzip zipfile1.zip zipfile2.zip zipfile3.zip zipfile4.zip

The first argument plays special role in unzip -- it specifies the archive to work with. Subsequent arguments are treated as files to extract. So this command attempts to extract zipfile2.zip, zipfile3.zip, and zipfile4.zip from the archive zipfile1.zip. Naturally this command fails unless zipfile1.zip actually contains files with those names.

The first method prevents the shell from expanding the wildcard by using single quotes. However, that only works if there is only one wildcard. The second and third methods work around that by running an explicit unzip command for each ZIP file found when the shell expands the wildcards, or returns the result of the ls command.

The ls version is used because the default behavior of bash (and sh) is to return unmatched patterns unchanged. That means you would be trying to unzip a file called /path/to/date*/name/*.zip if no files match the wildcard pattern. But command ls will simply return null on STDOUT, and an error that we throw away on STDERR.

You can set the shopt -s nullglob  option to cause filename patterns that match no files to expand to a null string, rather than themselves.

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 "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 unstructured files
-b path
Use the specified path for the temporary zip archive. For example:

zip -b /tmp stuff * 

will put the temporary zip archive in the directory /tmp, copying 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 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 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 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 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 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 recursion 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 archives 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 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.
-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 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 percentage 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 semicolons. 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 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 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 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 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 (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 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 oddities.

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 information 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 archives 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 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. If you do not escape wildcards in patterns it may seem to work but files in subdirectories 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 excluding 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 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 

-#

Regulate the speed of compression using the specified digit #, where -0 indicates no compression (store all files), -1 indicates 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 filename 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 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:

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 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.

When given the name of an existing zip archive, zip will replace identically 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 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 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 example,
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.

 

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:

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).

 


Recommended Links

Softpanorama hot topic of the month

Softpanorama Recommended

http://www.info-zip.org/pub/infozip

Reference

zip [-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

Reference

zip 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 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 compressing unused files or directories.

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 compression. zip automatically chooses the better of the two for each file to be compressed.

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 Also

compress(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 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 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.

Bugs

zip 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 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 DECnet 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 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 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 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 format, and .ZIP filename 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 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.



Etc

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History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOSProgramming Languages History : PL/1 : Simula 67 : C : History of GCC developmentScripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-MonthHow to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Haterís Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

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The Last but not Least


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