Provided by: unzip_6.0-21ubuntu1.2_amd64 
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(1), 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(1) mode. If the first option on the command line is -Z, the remaining options are taken
to be zipinfo(1) 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(1) 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(1), or with the -N option of the Amiga port of zip(1), 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(1), 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(1) and zipcloak(1) 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(1), zip(1), zipcloak(1), zipgrep(1), zipinfo(1), zipnote(1), zipsplit(1)
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)