unzip(1)
UNZIP(1L) MISC. REFERENCE MANUAL PAGES 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 sys-
tem). 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 `^') fol-
lows the left bracket, then the range of charac-
ters 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, par-
ticularly 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 sup-
ported, as with any other ZIP archive; just specify the
.exe suffix (if any) explicitly.
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[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 (wild-
cards) 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 sys-
tem.
[-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 direc-
tories 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 per-
mission 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 specifi-
cation, 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 there-
fore 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
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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 automati-
cally 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 overwrit-
ing, 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 typi-
cal 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 speci-
fied file in memory and compares the CRC (cyclic redun-
dancy 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
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zipfiles (e.g., ``unzip -T \*.zip'') and is much fas-
ter.
-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 compres-
sion 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 nor-
mal 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 sys-
tem 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, con-
verting line endings, end-of-file characters and the
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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 car-
riage 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 Sys-
tem use EBCDIC rather than the more common ASCII char-
acter 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 conver-
sions). 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, num-
bered 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 cir-
cumstances. For example, when unzip is run in
overwrite-all mode, an existing ``foo~'' file is
deleted before unzip attempts to rename ``foo'' to
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``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 max-
imum 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 plat-
forms, unzip's default behavior is to match both wild-
card 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 specifica-
tions). 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
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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 times-
tamps 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 dur-
ing 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 file-
type 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;
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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 sys-
tems 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
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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). Ordi-
narily 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 particu-
lar 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 han-
dling. 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 charac-
ters, 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 recogni-
tion 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.
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-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 charac-
ter `/'. (The two-character sequence ``**'' acts as a
multi-char wildcard that includes the directory separa-
tor 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 pat-
tern matching rules for both wildcard zipfile specifi-
cations 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 spe-
cial system privileges, and doubling the option (-XX)
under NT instructs unzip to use privileges for extrac-
tion; 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 espe-
cially compatible with OS/2's, so no attempt is made at
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cross-platform portability of access privileges. It is
not clear under what conditions this would ever be use-
ful 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 multi-
ple directory trees at the level of the current extrac-
tion 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. Gen-
erally, this allows to embed ASCII control characters
(or even sophisticated control sequences) in file
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names, at least on 'native' Unix file systems. How-
ever, 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 filter-
ing. 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). There-
fore, 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 sys-
tem; 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 over-
ride an environment option, one may use the ``minus opera-
tor'' to remove it. For instance, to override one of the
quiet-flags in the example above, use the command
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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 can-
cel 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 confus-
ing, 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 con-
fused 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 sup-
port 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 diag-
nostic screen (see the -v option above) for ``[decryption]''
as one of the special compilation options.
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As noted above, the -P option may be used to supply a pass-
word 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 gen-
erated for the extracted data or else unzip will fail during
the extraction because the ``decrypted'' bytes do not con-
stitute 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 extrac-
tion errors, as noted above.)
Archives encrypted with 8-bit passwords (for example, pass-
words 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 charac-
ters, 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
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UNZIP(1L) MISC. REFERENCE MANUAL PAGES UNZIP(1L)
password; the built-in attempts to check the password in
translated encoding have not yet been adapted for UTF-8 sup-
port 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 indi-
cating 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):
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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 con-
tain 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
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useful to define a pair of aliases: tt for ``unzip -tq''
and ii for ``unzip -Z'' (or ``zipinfo''). One may then sim-
ply 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 success-
fully 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.
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UNZIP(1L) MISC. REFERENCE MANUAL PAGES UNZIP(1L)
50 the disk is (or was) full during extraction.
51 the end of the ZIP archive was encountered prema-
turely.
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 unsup-
ported 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 con-
junction 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 defin-
itely 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 charac-
ters (and similar control sequences) are not taken into
account, they are handled as ordinary printable characters.
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Second, depending on the actual system / OS port, unzip may
not detect the true screen geometry but rather rely on "com-
monly 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 zip-
files (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 sym-
bolic (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 nor-
mally (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
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UNZIP(1L) MISC. REFERENCE MANUAL PAGES UNZIP(1L)
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 Her-
borth (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 origi-
nal mailing list at WSMR-SimTel20. The full list of contri-
butors to UnZip has grown quite large; please refer to the
CONTRIBS file in the UnZip source distribution for a rela-
tively 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
Info-ZIP Last change: 20 April 2009 (v6.0) 20
UNZIP(1L) MISC. REFERENCE MANUAL PAGES UNZIP(1L)
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 Last change: 20 April 2009 (v6.0) 21
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