UNZIP(1L) manual page
Table of Contents
unzip - list, test and extract compressed files in a ZIP
archive
unzip [-Z] [-cflptTuvz[abjnoqsCDKLMUVWX$/:^]] file[.zip] [file(s) ...]
[-x xfile(s) ...] [-d exdir]
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.
- 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.
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.
- -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.
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.
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.
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.)
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’’.
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.
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.
funzip(1L)
, zip(1L)
, zipcloak(1L)
, zipgrep(1L)
, zipinfo(1L)
, zipnote(1L)
,
zipsplit(1L)
The Info-ZIP home page is currently at
http://www.info-zip.org/pub/infozip/
or
ftp://ftp.info-zip.org/pub/infozip/ .
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.
- v1.2t15 Mar 89
- Samuel
H. Smith
- v2.0t 9 Sep 89
- Samuel H. Smith
- v2.xtfall 1989
- many Usenet contributors
- v3.0t 1 May 90
- Info-ZIP (DPK, consolidator)
- v3.1t15 Aug 90
- Info-ZIP (DPK, consolidator)
- v4.0t 1 Dec 90
- Info-ZIP (GRR, maintainer)
- v4.1t12 May 91
- Info-ZIP
- v4.2t20 Mar 92
- Info-ZIP
(Zip-Bugs subgroup, GRR)
- v5.0t21 Aug 92
- Info-ZIP (Zip-Bugs subgroup, GRR)
- v5.01t15
Jan 93
- Info-ZIP (Zip-Bugs subgroup, GRR)
- v5.1t 7 Feb 94
- Info-ZIP (Zip-Bugs subgroup,
GRR)
- v5.11t 2 Aug 94
- Info-ZIP (Zip-Bugs subgroup, GRR)
- v5.12t28 Aug 94
- Info-ZIP
(Zip-Bugs subgroup, GRR)
- v5.2t30 Apr 96
- Info-ZIP (Zip-Bugs subgroup, GRR)
- v5.3t22
Apr 97
- Info-ZIP (Zip-Bugs subgroup, GRR)
- v5.31t31 May 97
- Info-ZIP (Zip-Bugs subgroup,
GRR)
- v5.32t 3 Nov 97
- Info-ZIP (Zip-Bugs subgroup, GRR)
- v5.4t28 Nov 98
- Info-ZIP
(Zip-Bugs subgroup, SPC)
- v5.41t16 Apr 00
- Info-ZIP (Zip-Bugs subgroup, SPC)
- v5.42t14
Jan 01
- Info-ZIP (Zip-Bugs subgroup, SPC)
- v5.5t17 Feb 02
- Info-ZIP (Zip-Bugs subgroup,
SPC)
- v5.51t22 May 04
- Info-ZIP (Zip-Bugs subgroup, SPC)
- v5.52t28 Feb 05
- Info-ZIP
(Zip-Bugs subgroup, SPC)
- v6.0t20 Apr 09
- Info-ZIP (Zip-Bugs subgroup, SPC)
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