UNZIP(1L) UNZIP(1L)

NAME

unzip - list, test and extract compressed files in a ZIP archive

SYNOPSIS

unzip [-Z] [-cflptTuvz[abjnoqsCDKLMUVWX$/:^]] file[.zip]
[file(s) ...] [-x xfile(s) ...] [-d exdir]

DESCRIPTION

unzip will list, test, or extract files from a ZIP archive, commonly
found on MS-DOS systems. The default behavior (with no options) is
to extract into the current directory (and subdirectories below it)
all files from the specified ZIP archive. A companion program,
zip(1L), creates ZIP archives; both programs are compatible with
archives created by PKWARE's PKZIP and PKUNZIP for MS-DOS, but in
many cases the program options or default behaviors differ.

ARGUMENTS

file[.zip]
Path of the ZIP archive(s). If the file specification is a
wildcard, each matching file is processed in an order
determined by the operating system (or file system). Only the
filename can be a wildcard; the path itself cannot. Wildcard
expressions are similar to those supported in commonly used
Unix shells (sh, ksh, csh) and may contain:

* matches a sequence of 0 or more characters

? matches exactly 1 character

[...] matches any single character found inside the brackets;
ranges are specified by a beginning character, a
hyphen, and an ending character. If an exclamation
point or a caret (`!' or `^') follows the left bracket,
then the range of characters within the brackets is
complemented (that is, anything except the characters
inside the brackets is considered a match). To specify
a verbatim left bracket, the three-character sequence
``[[]'' has to be used.

(Be sure to quote any character that might otherwise be
interpreted or modified by the operating system, particularly
under Unix and VMS.) If no matches are found, the
specification is assumed to be a literal filename; and if that
also fails, the suffix .zip is appended. Note that self-
extracting ZIP files are supported, as with any other ZIP
archive; just specify the .exe suffix (if any) explicitly.

[file(s)]
An optional list of archive members to be processed, separated
by spaces. (VMS versions compiled with VMSCLI defined must
delimit files with commas instead. See -v in OPTIONS below.)
Regular expressions (wildcards) may be used to match multiple
members; see above. Again, be sure to quote expressions that
would otherwise be expanded or modified by the operating
system.

[-x xfile(s)]
An optional list of archive members to be excluded from
processing. Since wildcard characters normally match (`/')
directory separators (for exceptions see the option -W), this
option may be used to exclude any files that are in
subdirectories. For example, ``unzip foo *.[ch] -x */*''
would extract all C source files in the main directory, but
none in any subdirectories. Without the -x option, all C
source files in all directories within the zipfile would be
extracted.

[-d exdir]
An optional directory to which to extract files. By default,
all files and subdirectories are recreated in the current
directory; the -d option allows extraction in an arbitrary
directory (always assuming one has permission to write to the
directory). This option need not appear at the end of the
command line; it is also accepted before the zipfile
specification (with the normal options), immediately after the
zipfile specification, or between the file(s) and the -x
option. The option and directory may be concatenated without
any white space between them, but note that this may cause
normal shell behavior to be suppressed. In particular,
``-d ~'' (tilde) is expanded by Unix C shells into the name of
the user's home directory, but ``-d~'' is treated as a literal
subdirectory ``~'' of the current directory.

OPTIONS

Note that, in order to support obsolescent hardware, unzip's usage
screen is limited to 22 or 23 lines and should therefore be
considered only a reminder of the basic unzip syntax rather than an
exhaustive list of all possible flags. The exhaustive list follows:

-Z zipinfo(1L) mode. If the first option on the command line is
-Z, the remaining options are taken to be zipinfo(1L) options.
See the appropriate manual page for a description of these
options.

-A [OS/2, Unix DLL] print extended help for the DLL's programming
interface (API).

-c extract files to stdout/screen (``CRT''). This option is
similar to the -p option except that the name of each file is
printed as it is extracted, the -a option is allowed, and
ASCII-EBCDIC conversion is automatically performed if
appropriate. This option is not listed in the unzip usage
screen.

-f freshen existing files, i.e., extract only those files that
already exist on disk and that are newer than the disk copies.
By default unzip queries before overwriting, but the -o option
may be used to suppress the queries. Note that under many
operating systems, the TZ (timezone) environment variable must
be set correctly in order for -f and -u to work properly
(under Unix the variable is usually set automatically). The
reasons for this are somewhat subtle but have to do with the
differences between DOS-format file times (always local time)
and Unix-format times (always in GMT/UTC) and the necessity to
compare the two. A typical TZ value is ``PST8PDT'' (US
Pacific time with automatic adjustment for Daylight Savings
Time or ``summer time'').

-l list archive files (short format). The names, uncompressed
file sizes and modification dates and times of the specified
files are printed, along with totals for all files specified.
If UnZip was compiled with OS2_EAS defined, the -l option also
lists columns for the sizes of stored OS/2 extended attributes
(EAs) and OS/2 access control lists (ACLs). In addition, the
zipfile comment and individual file comments (if any) are
displayed. If a file was archived from a single-case file
system (for example, the old MS-DOS FAT file system) and the
-L option was given, the filename is converted to lowercase
and is prefixed with a caret (^).

-p extract files to pipe (stdout). Nothing but the file data is
sent to stdout, and the files are always extracted in binary
format, just as they are stored (no conversions).

-t test archive files. This option extracts each specified file
in memory and compares the CRC (cyclic redundancy check, an
enhanced checksum) of the expanded file with the original
file's stored CRC value.

-T [most OSes] set the timestamp on the archive(s) to that of the
newest file in each one. This corresponds to zip's -go option
except that it can be used on wildcard zipfiles (e.g., ``unzip
-T \*.zip'') and is much faster.

-u update existing files and create new ones if needed. This
option performs the same function as the -f option, extracting
(with query) files that are newer than those with the same
name on disk, and in addition it extracts those files that do
not already exist on disk. See -f above for information on
setting the timezone properly.

-v list archive files (verbose format) or show diagnostic version
info. This option has evolved and now behaves as both an
option and a modifier. As an option it has two purposes:
when a zipfile is specified with no other options, -v lists
archive files verbosely, adding to the basic -l info the
compression method, compressed size, compression ratio and
32-bit CRC. In contrast to most of the competing utilities,
unzip removes the 12 additional header bytes of encrypted
entries from the compressed size numbers. Therefore,
compressed size and compression ratio figures are independent
of the entry's encryption status and show the correct
compression performance. (The complete size of the encrypted
compressed data stream for zipfile entries is reported by the
more verbose zipinfo(1L) reports, see the separate manual.)
When no zipfile is specified (that is, the complete command is
simply ``unzip -v''), a diagnostic screen is printed. In
addition to the normal header with release date and version,
unzip lists the home Info-ZIP ftp site and where to find a
list of other ftp and non-ftp sites; the target operating
system for which it was compiled, as well as (possibly) the
hardware on which it was compiled, the compiler and version
used, and the compilation date; any special compilation
options that might affect the program's operation (see also
DECRYPTION below); and any options stored in environment
variables that might do the same (see ENVIRONMENT OPTIONS
below). As a modifier it works in conjunction with other
options (e.g., -t) to produce more verbose or debugging
output; this is not yet fully implemented but will be in
future releases.

-z display only the archive comment.

MODIFIERS

-a convert text files. Ordinarily all files are extracted
exactly as they are stored (as ``binary'' files). The -a
option causes files identified by zip as text files (those
with the `t' label in zipinfo listings, rather than `b') to be
automatically extracted as such, converting line endings, end-
of-file characters and the character set itself as necessary.
(For example, Unix files use line feeds (LFs) for end-of-line
(EOL) and have no end-of-file (EOF) marker; Macintoshes use
carriage returns (CRs) for EOLs; and most PC operating systems
use CR+LF for EOLs and control-Z for EOF. In addition, IBM
mainframes and the Michigan Terminal System use EBCDIC rather
than the more common ASCII character set, and NT supports
Unicode.) Note that zip's identification of text files is by
no means perfect; some ``text'' files may actually be binary
and vice versa. unzip therefore prints ``[text]'' or
``[binary]'' as a visual check for each file it extracts when
using the -a option. The -aa option forces all files to be
extracted as text, regardless of the supposed file type. On
VMS, see also -S.

-b [general] treat all files as binary (no text conversions).
This is a shortcut for ---a.

-b [Tandem] force the creation files with filecode type 180 ('C')
when extracting Zip entries marked as "text". (On Tandem, -a
is enabled by default, see above).

-b [VMS] auto-convert binary files (see -a above) to fixed-
length, 512-byte record format. Doubling the option (-bb)
forces all files to be extracted in this format. When
extracting to standard output (-c or -p option in effect), the
default conversion of text record delimiters is disabled for
binary (-b) resp. all (-bb) files.

-B [when compiled with UNIXBACKUP defined] save a backup copy of
each overwritten file. The backup file is gets the name of the
target file with a tilde and optionally a unique sequence
number (up to 5 digits) appended. The sequence number is
applied whenever another file with the original name plus
tilde already exists. When used together with the "overwrite
all" option -o, numbered backup files are never created. In
this case, all backup files are named as the original file
with an appended tilde, existing backup files are deleted
without notice. This feature works similarly to the default
behavior of emacs(1) in many locations.

Example: the old copy of ``foo'' is renamed to ``foo~''.

Warning: Users should be aware that the -B option does not
prevent loss of existing data under all circumstances. For
example, when unzip is run in overwrite-all mode, an existing
``foo~'' file is deleted before unzip attempts to rename
``foo'' to ``foo~''. When this rename attempt fails (because
of a file locks, insufficient privileges, or ...), the
extraction of ``foo~'' gets cancelled, but the old backup file
is already lost. A similar scenario takes place when the
sequence number range for numbered backup files gets exhausted
(99999, or 65535 for 16-bit systems). In this case, the
backup file with the maximum sequence number is deleted and
replaced by the new backup version without notice.

-C use case-insensitive matching for the selection of archive
entries from the command-line list of extract selection
patterns. unzip's philosophy is ``you get what you ask for''
(this is also responsible for the -L/-U change; see the
relevant options below). Because some file systems are fully
case-sensitive (notably those under the Unix operating system)
and because both ZIP archives and unzip itself are portable
across platforms, unzip's default behavior is to match both
wildcard and literal filenames case-sensitively. That is,
specifying ``makefile'' on the command line will only match
``makefile'' in the archive, not ``Makefile'' or ``MAKEFILE''
(and similarly for wildcard specifications). Since this does
not correspond to the behavior of many other operating/file
systems (for example, OS/2 HPFS, which preserves mixed case
but is not sensitive to it), the -C option may be used to
force all filename matches to be case-insensitive. In the
example above, all three files would then match ``makefile''
(or ``make*'', or similar). The -C option affects file specs
in both the normal file list and the excluded-file list
(xlist).

Please note that the -C option does neither affect the search
for the zipfile(s) nor the matching of archive entries to
existing files on the extraction path. On a case-sensitive
file system, unzip will never try to overwrite a file ``FOO''
when extracting an entry ``foo''!

-D skip restoration of timestamps for extracted items. Normally,
unzip tries to restore all meta-information for extracted
items that are supplied in the Zip archive (and do not require
privileges or impose a security risk). By specifying -D,
unzip is told to suppress restoration of timestamps for
directories explicitly created from Zip archive entries. This
option only applies to ports that support setting timestamps
for directories (currently ATheOS, BeOS, MacOS, OS/2, Unix,
VMS, Win32, for other unzip ports, -D has no effect). The
duplicated option -DD forces suppression of timestamp
restoration for all extracted entries (files and directories).
This option results in setting the timestamps for all
extracted entries to the current time.

On VMS, the default setting for this option is -D for
consistency with the behaviour of BACKUP: file timestamps are
restored, timestamps of extracted directories are left at the
current time. To enable restoration of directory timestamps,
the negated option --D should be specified. On VMS, the
option -D disables timestamp restoration for all extracted Zip
archive items. (Here, a single -D on the command line
combines with the default -D to do what an explicit -DD does
on other systems.)

-E [MacOS only] display contents of MacOS extra field during
restore operation.

-F [Acorn only] suppress removal of NFS filetype extension from
stored filenames.

-F [non-Acorn systems supporting long filenames with embedded
commas, and only if compiled with ACORN_FTYPE_NFS defined]
translate filetype information from ACORN RISC OS extra field
blocks into a NFS filetype extension and append it to the
names of the extracted files. (When the stored filename
appears to already have an appended NFS filetype extension, it
is replaced by the info from the extra field.)

-i [MacOS only] ignore filenames stored in MacOS extra fields.
Instead, the most compatible filename stored in the generic
part of the entry's header is used.

-j junk paths. The archive's directory structure is not
recreated; all files are deposited in the extraction directory
(by default, the current one).

-J [BeOS only] junk file attributes. The file's BeOS file
attributes are not restored, just the file's data.

-J [MacOS only] ignore MacOS extra fields. All Macintosh
specific info is skipped. Data-fork and resource-fork are
restored as separate files.

-K [AtheOS, BeOS, Unix only] retain SUID/SGID/Tacky file
attributes. Without this flag, these attribute bits are
cleared for security reasons.

-L convert to lowercase any filename originating on an uppercase-
only operating system or file system. (This was unzip's
default behavior in releases prior to 5.11; the new default
behavior is identical to the old behavior with the -U option,
which is now obsolete and will be removed in a future
release.) Depending on the archiver, files archived under
single-case file systems (VMS, old MS-DOS FAT, etc.) may be
stored as all-uppercase names; this can be ugly or
inconvenient when extracting to a case-preserving file system
such as OS/2 HPFS or a case-sensitive one such as under Unix.
By default unzip lists and extracts such filenames exactly as
they're stored (excepting truncation, conversion of
unsupported characters, etc.); this option causes the names of
all files from certain systems to be converted to lowercase.
The -LL option forces conversion of every filename to
lowercase, regardless of the originating file system.

-M pipe all output through an internal pager similar to the Unix
more(1) command. At the end of a screenful of output, unzip
pauses with a ``--More--'' prompt; the next screenful may be
viewed by pressing the Enter (Return) key or the space bar.
unzip can be terminated by pressing the ``q'' key and, on some
systems, the Enter/Return key. Unlike Unix more(1), there is
no forward-searching or editing capability. Also, unzip
doesn't notice if long lines wrap at the edge of the screen,
effectively resulting in the printing of two or more lines and
the likelihood that some text will scroll off the top of the
screen before being viewed. On some systems the number of
available lines on the screen is not detected, in which case
unzip assumes the height is 24 lines.

-n never overwrite existing files. If a file already exists,
skip the extraction of that file without prompting. By
default unzip queries before extracting any file that already
exists; the user may choose to overwrite only the current
file, overwrite all files, skip extraction of the current
file, skip extraction of all existing files, or rename the
current file.

-N [Amiga] extract file comments as Amiga filenotes. File
comments are created with the -c option of zip(1L), or with
the -N option of the Amiga port of zip(1L), which stores
filenotes as comments.

-o overwrite existing files without prompting. This is a
dangerous option, so use it with care. (It is often used with
-f, however, and is the only way to overwrite directory EAs
under OS/2.)

-P password
use password to decrypt encrypted 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 perform operations quietly (-qq = even quieter). Ordinarily
unzip prints the names of the files it's extracting or
testing, the extraction methods, any file or zipfile comments
that may be stored in the archive, and possibly a summary when
finished with each archive. The -q[q] options suppress the
printing of some or all of these messages.

-s [OS/2, NT, MS-DOS] convert spaces in filenames to underscores.
Since all PC operating systems allow spaces in filenames,
unzip by default extracts filenames with spaces intact (e.g.,
``EA DATA. SF''). This can be awkward, however, since MS-DOS
in particular does not gracefully support spaces in filenames.
Conversion of spaces to underscores can eliminate the
awkwardness in some cases.

-S [VMS] convert text files (-a, -aa) into Stream_LF record
format, instead of the text-file default, variable-length
record format. (Stream_LF is the default record format of VMS
unzip. It is applied unless conversion (-a, -aa and/or -b,
-bb) is requested or a VMS-specific entry is processed.)

-U [UNICODE_SUPPORT only] modify or disable UTF-8 handling. When
UNICODE_SUPPORT is available, the option -U forces unzip to
escape all non-ASCII characters from UTF-8 coded filenames as
``#Uxxxx'' (for UCS-2 characters, or ``#Lxxxxxx'' for unicode
codepoints needing 3 octets). This option is mainly provided
for debugging purpose when the fairly new UTF-8 support is
suspected to mangle up extracted filenames.

The option -UU allows to entirely disable the recognition of
UTF-8 encoded filenames. The handling of filename codings
within unzip falls back to the behaviour of previous versions.

[old, obsolete usage] leave filenames uppercase if created
under MS-DOS, VMS, etc. See -L above.

-V retain (VMS) file version numbers. VMS files can be stored
with a version number, in the format file.ext;##. By default
the ``;##'' version numbers are stripped, but this option
allows them to be retained. (On file systems that limit
filenames to particularly short lengths, the version numbers
may be truncated or stripped regardless of this option.)

-W [only when WILD_STOP_AT_DIR compile-time option enabled]
modifies the pattern matching routine so that both `?'
(single-char wildcard) and `*' (multi-char wildcard) do not
match the directory separator character `/'. (The two-
character sequence ``**'' acts as a multi-char wildcard that
includes the directory separator in its matched characters.)
Examples:

"*.c" matches "foo.c" but not "mydir/foo.c"
"**.c" matches both "foo.c" and "mydir/foo.c"
"*/*.c" matches "bar/foo.c" but not "baz/bar/foo.c"
"??*/*" matches "ab/foo" and "abc/foo"
but not "a/foo" or "a/b/foo"

This modified behaviour is equivalent to the pattern matching
style used by the shells of some of UnZip's supported target
OSs (one example is Acorn RISC OS). This option may not be
available on systems where the Zip archive's internal
directory separator character `/' is allowed as regular
character in native operating system filenames. (Currently,
UnZip uses the same pattern matching rules for both wildcard
zipfile specifications and zip entry selection patterns in
most ports. For systems allowing `/' as regular filename
character, the -W option would not work as expected on a
wildcard zipfile specification.)

-X [VMS, Unix, OS/2, NT, Tandem] restore owner/protection info
(UICs and ACL entries) under VMS, or user and group info
(UID/GID) under Unix, or access control lists (ACLs) under
certain network-enabled versions of OS/2 (Warp Server with IBM
LAN Server/Requester 3.0 to 5.0; Warp Connect with IBM Peer
1.0), or security ACLs under Windows NT. In most cases this
will require special system privileges, and doubling the
option (-XX) under NT instructs unzip to use privileges for
extraction; but under Unix, for example, a user who belongs to
several groups can restore files owned by any of those groups,
as long as the user IDs match his or her own. Note that
ordinary file attributes are always restored--this option
applies only to optional, extra ownership info available on
some operating systems. [NT's access control lists do not
appear to be especially compatible with OS/2's, so no attempt
is made at cross-platform portability of access privileges.
It is not clear under what conditions this would ever be
useful anyway.]

-Y [VMS] treat archived file name endings of ``.nnn'' (where
``nnn'' is a decimal number) as if they were VMS version
numbers (``;nnn''). (The default is to treat them as file
types.) Example:
"a.b.3" -> "a.b;3".

-$ [MS-DOS, OS/2, NT] restore the volume label if the extraction
medium is removable (e.g., a diskette). Doubling the option
(-$$) allows fixed media (hard disks) to be labelled as well.
By default, volume labels are ignored.

-/ extensions
[Acorn only] overrides the extension list supplied by
Unzip$Ext environment variable. During extraction, filename
extensions that match one of the items in this extension list
are swapped in front of the base name of the extracted file.

-: [all but Acorn, VM/CMS, MVS, Tandem] allows to extract archive
members into locations outside of the current `` extraction
root folder''. For security reasons, unzip normally removes
``parent dir'' path components (``../'') from the names of
extracted file. This safety feature (new for version 5.50)
prevents unzip from accidentally writing files to
``sensitive'' areas outside the active extraction folder tree
head. The -: option lets unzip switch back to its previous,
more liberal behaviour, to allow exact extraction of (older)
archives that used ``../'' components to create multiple
directory trees at the level of the current extraction folder.
This option does not enable writing explicitly to the root
directory (``/''). To achieve this, it is necessary to set
the extraction target folder to root (e.g. -d / ). However,
when the -: option is specified, it is still possible to
implicitly write to the root directory by specifying enough
``../'' path components within the zip archive. Use this
option with extreme caution.

-^ [Unix only] allow control characters in names of extracted ZIP
archive entries. On Unix, a file name may contain any (8-bit)
character code with the two exception '/' (directory
delimiter) and NUL (0x00, the C string termination indicator),
unless the specific file system has more restrictive
conventions. Generally, this allows to embed ASCII control
characters (or even sophisticated control sequences) in file
names, at least on 'native' Unix file systems. However, it
may be highly suspicious to make use of this Unix "feature".
Embedded control characters in file names might have nasty
side effects when displayed on screen by some listing code
without sufficient filtering. And, for ordinary users, it may
be difficult to handle such file names (e.g. when trying to
specify it for open, copy, move, or delete operations).
Therefore, unzip applies a filter by default that removes
potentially dangerous control characters from the extracted
file names. The -^ option allows to override this filter in
the rare case that embedded filename control characters are to
be intentionally restored.

-2 [VMS] force unconditionally conversion of file names to
ODS2-compatible names. The default is to exploit the
destination file system, preserving case and extended file
name characters on an ODS5 destination file system; and
applying the ODS2-compatibility file name filtering on an ODS2
destination file system.

ENVIRONMENT OPTIONS

unzip's default behavior may be modified via options placed in an
environment variable. This can be done with any option, but it is
probably most useful with the -a, -L, -C, -q, -o, or -n modifiers:
make unzip auto-convert text files by default, make it convert
filenames from uppercase systems to lowercase, make it match names
case-insensitively, make it quieter, or make it always overwrite or
never overwrite files as it extracts them. For example, to make
unzip act as quietly as possible, only reporting errors, one would
use one of the following commands:

Unix Bourne shell:
UNZIP=-qq; export UNZIP

Unix C shell:
setenv UNZIP -qq

OS/2 or MS-DOS:
set UNZIP=-qq

VMS (quotes for lowercase):
define UNZIP_OPTS "-qq"

Environment options are, in effect, considered to be just like any
other command-line options, except that they are effectively the
first options on the command line. To override an environment
option, one may use the ``minus operator'' to remove it. For
instance, to override one of the quiet-flags in the example above,
use the command

unzip --q[other options] zipfile

The first hyphen is the normal switch character, and the second is a
minus sign, acting on the q option. Thus the effect here is to
cancel one quantum of quietness. To cancel both quiet flags, two (or
more) minuses may be used:

unzip -t--q zipfile
unzip ---qt zipfile

(the two are equivalent). This may seem awkward or confusing, but it
is reasonably intuitive: just ignore the first hyphen and go from
there. It is also consistent with the behavior of Unix nice(1).

As suggested by the examples above, the default variable names are
UNZIP_OPTS for VMS (where the symbol used to install unzip as a
foreign command would otherwise be confused with the environment
variable), and UNZIP for all other operating systems. For
compatibility with zip(1L), UNZIPOPT is also accepted (don't ask).
If both UNZIP and UNZIPOPT are defined, however, UNZIP takes
precedence. unzip's diagnostic option (-v with no zipfile name) can
be used to check the values of all four possible unzip and zipinfo
environment variables.

The timezone variable (TZ) should be set according to the local
timezone in order for the -f and -u to operate correctly. See the
description of -f above for details. This variable may also be
necessary to get timestamps of extracted files to be set correctly.
The WIN32 (Win9x/ME/NT4/2K/XP/2K3) port of unzip gets the timezone
configuration from the registry, assuming it is correctly set in the
Control Panel. The TZ variable is ignored for this port.

DECRYPTION

Encrypted archives are fully supported by Info-ZIP software, but due
to United States export restrictions, de-/encryption support might be
disabled in your compiled binary. However, since spring 2000, US
export restrictions have been liberated, and our source archives do
now include full crypt code. In case you need binary distributions
with crypt support enabled, see the file ``WHERE'' in any Info-ZIP
source or binary distribution for locations both inside and outside
the US.

Some compiled versions of unzip may not support decryption. To check
a version for crypt support, either attempt to test or extract an
encrypted archive, or else check unzip's diagnostic screen (see the
-v option above) for ``[decryption]'' as one of the special
compilation options.

As noted above, the -P option may be used to supply a password on the
command line, but at a cost in security. The preferred decryption
method is simply to extract normally; if a zipfile member is
encrypted, unzip will prompt for the password without echoing what is
typed. unzip continues to use the same password as long as it
appears to be valid, by testing a 12-byte header on each file. The
correct password will always check out against the header, but there
is a 1-in-256 chance that an incorrect password will as well. (This
is a security feature of the PKWARE zipfile format; it helps prevent
brute-force attacks that might otherwise gain a large speed advantage
by testing only the header.) In the case that an incorrect password
is given but it passes the header test anyway, either an incorrect
CRC will be generated for the extracted data or else unzip will fail
during the extraction because the ``decrypted'' bytes do not
constitute a valid compressed data stream.

If the first password fails the header check on some file, unzip will
prompt for another password, and so on until all files are extracted.
If a password is not known, entering a null password (that is, just a
carriage return or ``Enter'') is taken as a signal to skip all
further prompting. Only unencrypted files in the archive(s) will
thereafter be extracted. (In fact, that's not quite true; older
versions of zip(1L) and zipcloak(1L) allowed null passwords, so unzip
checks each encrypted file to see if the null password works. This
may result in ``false positives'' and extraction errors, as noted
above.)

Archives encrypted with 8-bit passwords (for example, passwords with
accented European characters) may not be portable across systems
and/or other archivers. This problem stems from the use of multiple
encoding methods for such characters, including Latin-1 (ISO 8859-1)
and OEM code page 850. DOS PKZIP 2.04g uses the OEM code page;
Windows PKZIP 2.50 uses Latin-1 (and is therefore incompatible with
DOS PKZIP); Info-ZIP uses the OEM code page on DOS, OS/2 and Win3.x
ports but ISO coding (Latin-1 etc.) everywhere else; and Nico Mak's
WinZip 6.x does not allow 8-bit passwords at all. UnZip 5.3 (or
newer) attempts to use the default character set first (e.g.,
Latin-1), followed by the alternate one (e.g., OEM code page) to test
passwords. On EBCDIC systems, if both of these fail, EBCDIC encoding
will be tested as a last resort. (EBCDIC is not tested on non-EBCDIC
systems, because there are no known archivers that encrypt using
EBCDIC encoding.) ISO character encodings other than Latin-1 are not
supported. The new addition of (partially) Unicode (resp. UTF-8)
support in UnZip 6.0 has not yet been adapted to the encryption
password handling in unzip. On systems that use UTF-8 as native
character encoding, unzip simply tries decryption with the native
UTF-8 encoded password; the built-in attempts to check the password
in translated encoding have not yet been adapted for UTF-8 support
and will consequently fail.

EXAMPLES

To use unzip to extract all members of the archive letters.zip into
the current directory and subdirectories below it, creating any
subdirectories as necessary:

unzip letters

To extract all members of letters.zip into the current directory
only:

unzip -j letters

To test letters.zip, printing only a summary message indicating
whether the archive is OK or not:

unzip -tq letters

To test all zipfiles in the current directory, printing only the
summaries:

unzip -tq \*.zip

(The backslash before the asterisk is only required if the shell
expands wildcards, as in Unix; double quotes could have been used
instead, as in the source examples below.) To extract to standard
output all members of letters.zip whose names end in .tex, auto-
converting to the local end-of-line convention and piping the output
into more(1):

unzip -ca letters \*.tex | more

To extract the binary file paper1.dvi to standard output and pipe it
to a printing program:

unzip -p articles paper1.dvi | dvips

To extract all FORTRAN and C source files--*.f, *.c, *.h, and
Makefile--into the /tmp directory:

unzip source.zip "*.[fch]" Makefile -d /tmp

(the double quotes are necessary only in Unix and only if globbing is
turned on). To extract all FORTRAN and C source files, regardless of
case (e.g., both *.c and *.C, and any makefile, Makefile, MAKEFILE or
similar):

unzip -C source.zip "*.[fch]" makefile -d /tmp

To extract any such files but convert any uppercase MS-DOS or VMS
names to lowercase and convert the line-endings of all of the files
to the local standard (without respect to any files that might be
marked ``binary''):

unzip -aaCL source.zip "*.[fch]" makefile -d /tmp

To extract only newer versions of the files already in the current
directory, without querying (NOTE: be careful of unzipping in one
timezone a zipfile created in another--ZIP archives other than those
created by Zip 2.1 or later contain no timezone information, and a
``newer'' file from an eastern timezone may, in fact, be older):

unzip -fo sources

To extract newer versions of the files already in the current
directory and to create any files not already there (same caveat as
previous example):

unzip -uo sources

To display a diagnostic screen showing which unzip and zipinfo
options are stored in environment variables, whether decryption
support was compiled in, the compiler with which unzip was compiled,
etc.:

unzip -v

In the last five examples, assume that UNZIP or UNZIP_OPTS is set to
-q. To do a singly quiet listing:

unzip -l file.zip

To do a doubly quiet listing:

unzip -ql file.zip

(Note that the ``.zip'' is generally not necessary.) To do a
standard listing:

unzip --ql file.zip
or
unzip -l-q file.zip
or
unzip -l--q file.zip
(Extra minuses in options don't hurt.)

TIPS

The current maintainer, being a lazy sort, finds it very useful to
define a pair of aliases: tt for ``unzip -tq'' and ii for ``unzip
-Z'' (or ``zipinfo''). One may then simply type ``tt zipfile'' to
test an archive, something that is worth making a habit of doing.
With luck unzip will report ``No errors detected in compressed data
of zipfile.zip,'' after which one may breathe a sigh of relief.

The maintainer also finds it useful to set the UNZIP environment
variable to ``-aL'' and is tempted to add ``-C'' as well. His
ZIPINFO variable is set to ``-z''.

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.

1 one or more warning errors were encountered, but
processing completed successfully anyway. This
includes zipfiles where one or more files was skipped
due to unsupported compression method or encryption
with an unknown password.

2 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.

3 a severe error in the zipfile format was detected.
Processing probably failed immediately.

4 unzip was unable to allocate memory for one or more
buffers during program initialization.

5 unzip was unable to allocate memory or unable to obtain
a tty to read the decryption password(s).

6 unzip was unable to allocate memory during
decompression to disk.

7 unzip was unable to allocate memory during in-memory
decompression.

8 [currently not used]

9 the specified zipfiles were not found.

10 invalid options were specified on the command line.

11 no matching files were found.

50 the disk is (or was) full during extraction.

51 the end of the ZIP archive was encountered prematurely.

80 the user aborted unzip prematurely with control-C (or
similar)

81 testing or extraction of one or more files failed due
to unsupported compression methods or unsupported
decryption.

82 no files were found due to bad decryption password(s).
(If even one file is successfully processed, however,
the exit status is 1.)

VMS interprets standard Unix (or PC) return values as other, scarier-
looking things, so unzip instead maps them into VMS-style status
codes. The current mapping is as follows: 1 (success) for normal
exit, 0x7fff0001 for warning errors, and (0x7fff000? +
16*normal_unzip_exit_status) for all other errors, where the `?' is 2
(error) for unzip values 2, 9-11 and 80-82, and 4 (fatal error) for
the remaining ones (3-8, 50, 51). In addition, there is a
compilation option to expand upon this behavior: defining
RETURN_CODES results in a human-readable explanation of what the
error status means.

BUGS

Multi-part archives are not yet supported, except in conjunction with
zip. (All parts must be concatenated together in order, and then
``zip -F'' (for zip 2.x) or ``zip -FF'' (for zip 3.x) must be
performed on the concatenated archive in order to ``fix'' it. Also,
zip 3.0 and later can combine multi-part (split) archives into a
combined single-file archive using ``zip -s- inarchive -O
outarchive''. See the zip 3 manual page for more information.) This
will definitely be corrected in the next major release.

Archives read from standard input are not yet supported, except with
funzip (and then only the first member of the archive can be
extracted).

Archives encrypted with 8-bit passwords (e.g., passwords with
accented European characters) may not be portable across systems
and/or other archivers. See the discussion in DECRYPTION above.

unzip's -M (``more'') option tries to take into account automatic
wrapping of long lines. However, the code may fail to detect the
correct wrapping locations. First, TAB characters (and similar
control sequences) are not taken into account, they are handled as
ordinary printable characters. Second, depending on the actual
system / OS port, unzip may not detect the true screen geometry but
rather rely on "commonly used" default dimensions. The correct
handling of tabs would require the implementation of a query for the
actual tabulator setup on the output console.

Dates, times and permissions of stored directories are not restored
except under Unix. (On Windows NT and successors, timestamps are now
restored.)

[MS-DOS] When extracting or testing files from an archive on a
defective floppy diskette, if the ``Fail'' option is chosen from
DOS's ``Abort, Retry, Fail?'' message, older versions of unzip may
hang the system, requiring a reboot. This problem appears to be
fixed, but control-C (or control-Break) can still be used to
terminate unzip.

Under DEC Ultrix, unzip would sometimes fail on long zipfiles (bad
CRC, not always reproducible). This was apparently due either to a
hardware bug (cache memory) or an operating system bug (improper
handling of page faults?). Since Ultrix has been abandoned in favor
of Digital Unix (OSF/1), this may not be an issue anymore.

[Unix] Unix special files such as FIFO buffers (named pipes), block
devices and character devices are not restored even if they are
somehow represented in the zipfile, nor are hard-linked files
relinked. Basically the only file types restored by unzip are
regular files, directories and symbolic (soft) links.

[OS/2] Extended attributes for existing directories are only updated
if the -o (``overwrite all'') option is given. This is a limitation
of the operating system; because directories only have a creation
time associated with them, unzip has no way to determine whether the
stored attributes are newer or older than those on disk. In practice
this may mean a two-pass approach is required: first unpack the
archive normally (with or without freshening/updating existing
files), then overwrite just the directory entries (e.g., ``unzip -o
foo */'').

[VMS] When extracting to another directory, only the [.foo] syntax is
accepted for the -d option; the simple Unix foo syntax is silently
ignored (as is the less common VMS foo.dir syntax).

[VMS] When the file being extracted already exists, unzip's query
only allows skipping, overwriting or renaming; there should
additionally be a choice for creating a new version of the file. In
fact, the ``overwrite'' choice does create a new version; the old
version is not overwritten or deleted.

SEE ALSO

funzip(1L), zip(1L), zipcloak(1L), zipgrep(1L), zipinfo(1L),
zipnote(1L), zipsplit(1L)

URL

The Info-ZIP home page is currently at
http://www.info-zip.org/pub/infozip/
or
ftp://ftp.info-zip.org/pub/infozip/ .

AUTHORS

The primary Info-ZIP authors (current semi-active members of the Zip-
Bugs workgroup) are: Ed Gordon (Zip, general maintenance, shared
code, Zip64, Win32, Unix, Unicode); Christian Spieler (UnZip
maintenance coordination, VMS, MS-DOS, Win32, shared code, general
Zip and UnZip integration and optimization); Onno van der Linden
(Zip); Mike White (Win32, Windows GUI, Windows DLLs); Kai Uwe Rommel
(OS/2, Win32); Steven M. Schweda (VMS, Unix, support of new
features); Paul Kienitz (Amiga, Win32, Unicode); Chris Herborth
(BeOS, QNX, Atari); Jonathan Hudson (SMS/QDOS); Sergio Monesi (Acorn
RISC OS); Harald Denker (Atari, MVS); John Bush (Solaris, Amiga);
Hunter Goatley (VMS, Info-ZIP Site maintenance); Steve Salisbury
(Win32); Steve Miller (Windows CE GUI), Johnny Lee (MS-DOS, Win32,
Zip64); and Dave Smith (Tandem NSK).

The following people were former members of the Info-ZIP development
group and provided major contributions to key parts of the current
code: Greg ``Cave Newt'' Roelofs (UnZip, unshrink decompression);
Jean-loup Gailly (deflate compression); Mark Adler (inflate
decompression, fUnZip).

The author of the original unzip code upon which Info-ZIP's was based
is Samuel H. Smith; Carl Mascott did the first Unix port; and David
P. Kirschbaum organized and led Info-ZIP in its early days with
Keith Petersen hosting the original mailing list at WSMR-SimTel20.
The full list of contributors to UnZip has grown quite large; please
refer to the CONTRIBS file in the UnZip source distribution for a
relatively complete version.

VERSIONS

v1.2 15 Mar 89
Samuel H. Smith
v2.0 9 Sep 89
Samuel H. Smith
v2.x fall 1989
many Usenet contributors
v3.0 1 May 90
Info-ZIP (DPK, consolidator)
v3.1 15 Aug 90
Info-ZIP (DPK, consolidator)
v4.0 1 Dec 90
Info-ZIP (GRR, maintainer)
v4.1 12 May 91
Info-ZIP
v4.2 20 Mar 92
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.0 21 Aug 92
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.01 15 Jan 93
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.1 7 Feb 94
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.11 2 Aug 94
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.12 28 Aug 94
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.2 30 Apr 96
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.3 22 Apr 97
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.31 31 May 97
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.32 3 Nov 97
Info-ZIP (Zip-Bugs subgroup, GRR)
v5.4 28 Nov 98
Info-ZIP (Zip-Bugs subgroup, SPC)
v5.41 16 Apr 00
Info-ZIP (Zip-Bugs subgroup, SPC)
v5.42 14 Jan 01
Info-ZIP (Zip-Bugs subgroup, SPC)
v5.5 17 Feb 02
Info-ZIP (Zip-Bugs subgroup, SPC)
v5.51 22 May 04
Info-ZIP (Zip-Bugs subgroup, SPC)
v5.52 28 Feb 05
Info-ZIP (Zip-Bugs subgroup, SPC)
v6.0 20 Apr 09
Info-ZIP (Zip-Bugs subgroup, SPC)

Info-ZIP 20 April 2009 (v6.0) UNZIP(1L)