unzip.1

完整的解压zip文件的源码。包含密码功能

[MacOS only] ignore MacOS extra fields.  All Macintosh specific info
is skipped. Data-fork and resource-fork are restored as separate files.
.TP
.B \-L
convert to lowercase any filename originating on an uppercase-only operating
system or file system.  (This was \fIunzip\fP's default behavior in releases
prior to 5.11; the new default behavior is identical to the old behavior with
the \fB\-U\fP 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 \fIunzip\fP 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.
.TP
.B \-M
pipe all output through an internal pager similar to the Unix\fImore\fP(1)
command.  At the end of a screenful of output, \fIunzip\fP pauses with a
``\-\-More\-\-'' prompt; the next screenful may be viewed by pressing the
Enter (Return) key or the space bar.  \fIunzip\fP can be terminated by
pressing the ``q'' key and, on some systems, the Enter/Return key.  Unlike
Unix \fImore\fP(1), there is no forward-searching or editing capability.
Also, \fIunzip\fP 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 \fIunzip\fP assumes the height is 24 lines.
.TP
.B \-n
never overwrite existing files.  If a file already exists, skip the extraction
of that file without prompting.  By default \fIunzip\fP 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.
.TP
.B \-N
[Amiga] extract file comments as Amiga filenotes.  File comments are created
with the \-c option of \fIzip\fP(1L), or with the \-N option of the Amiga port
of \fIzip\fP(1L), which stores filenotes as comments.
.TP
.B \-o
overwrite existing files without prompting.  This is a dangerous option, so
use it with care.  (It is often used with \fB\-f\fP, however, and is the only
way to overwrite directory EAs under OS/2.)
.TP
.IP \fB\-P\fP\ \fIpassword\fP
use \fIpassword\fP to decrypt encrypted zipfile entries (if any).  \fBTHIS IS
INSECURE!\fP  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.)
.TP
.B \-q
perform operations quietly (\fB\-qq\fP = even quieter).  Ordinarily \fIunzip\fP
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 \fB\-q\fP[\fBq\fP]
options suppress the printing of some or all of these messages.
.TP
.B \-s
[OS/2, NT, MS-DOS] convert spaces in filenames to underscores.  Since all PC
operating systems allow spaces in filenames, \fIunzip\fP by default extracts
filenames with spaces intact (e.g., ``\fCEA\ DATA.\ SF\fR'').  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.
.TP
.B \-U
(obsolete; to be removed in a future release) leave filenames uppercase if
created under MS-DOS, VMS, etc.  See \fB\-L\fP above.
.TP
.B \-V
retain (VMS) file version numbers.  VMS files can be stored with a version
number, in the format \fCfile.ext;##\fR.  By default the ``\fC;##\fR'' 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.)
.TP
.B \-X
[VMS, Unix, OS/2, NT] restore owner/protection info (UICs) 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 (\fB\-XX\fP) under NT instructs \fIunzip\fP 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.]
.TP
.B \-$
.\" Amiga support possible eventually, but not yet
[MS-DOS, OS/2, NT] restore the volume label if the extraction medium is
removable (e.g., a diskette).  Doubling the option (\fB\-$$\fP) allows fixed
media (hard disks) to be labelled as well.  By default, volume labels are
ignored.
.PD
.\" =========================================================================
.SH "ENVIRONMENT OPTIONS"
\fIunzip\fP'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 \fB\-a\fP, \fB\-L\fP, \fB\-C\fP, \fB\-q\fP,
\fB\-o\fP, or \fB\-n\fP modifiers:  make \fIunzip\fP 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 \fIunzip\fP act as quietly as possible, only
reporting errors, one would use one of the following commands:
.PP
.DT
.ft CW
.in +4n
.ta \w'UNZIP=\-qq; export UNZIP'u+4n
.in
.ft
.PD 0
.Y "UNZIP=\-qq; export UNZIP\t\fRUnix Bourne shell"
.Y "setenv UNZIP \-qq\t\fRUnix C shell"
.Y "set UNZIP=\-qq\t\fROS/2 or MS-DOS"
.Y "define UNZIP_OPTS ""\-qq""\t\fRVMS (quotes for \fIlowercase\fP)"
.PD
.PP
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
.PP
.Y "unzip \-\-q[\fIother options\fC] zipfile"
.PP
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:
.PP
.PD 0
.Y "unzip \-t\-\-q zipfile"
.Y "unzip \-\-\-qt zipfile"
.PD
.PP
(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 \fInice\fP(1).
.PP
As suggested by the examples above, the default variable names are UNZIP_OPTS
for VMS (where the symbol used to install \fIunzip\fP as a foreign command
would otherwise be confused with the environment variable), and UNZIP
for all other operating systems.  For compatibility with \fIzip\fP(1L),
UNZIPOPT is also accepted (don't ask).  If both UNZIP and UNZIPOPT
are defined, however, UNZIP takes precedence.  \fIunzip\fP's diagnostic
option (\fB\-v\fP with no zipfile name) can be used to check the values
of all four possible \fIunzip\fP and \fIzipinfo\fP environment variables.
.PP
The timezone variable (TZ) should be set according to the local timezone
in order for the \fB\-f\fP and \fB\-u\fP to operate correctly.  See the
description of \fB\-f\fP above for details.  This variable may also be
necessary in order for timestamps on extracted files to be set correctly.
Under Windows 95/NT \fIunzip\fP should know the correct timezone even if
TZ is unset, assuming the timezone is correctly set in the Control Panel.
.PD
.\" =========================================================================
.SH DECRYPTION
Encrypted archives are fully supported by Info-ZIP software, but due to
United States export restrictions, the encryption and decryption sources
are not packaged with the regular \fIunzip\fP and \fIzip\fP distributions.
Since the crypt sources were written by Europeans, however, they are
freely available at sites throughout the world; see the file ``WHERE'' in
any Info-ZIP source or binary distribution for locations both inside and
outside the US.
.PP
Because of the separate distribution, not all compiled versions of \fIunzip\fP
support decryption.  To check a version for crypt support, either attempt to
test or extract an encrypted archive, or else check \fIunzip\fP's diagnostic
screen (see the \fB\-v\fP option above) for ``\fC[decryption]\fR'' as one of
the special compilation options.
.PP
As noted above, the \fB\-P\fP 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,
\fIunzip\fP will prompt for the password without echoing what is typed.
\fIunzip\fP 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 \fIunzip\fP
will fail during the extraction because the ``decrypted'' bytes do not
constitute a valid compressed data stream.
.PP
If the first password fails the header check on some file, \fIunzip\fP 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 \fIzip\fP(1L) and
\fIzipcloak\fP(1L) allowed null passwords, so \fIunzip\fP checks each encrypted
file to see if the null password works.  This may result in ``false positives''
and extraction errors, as noted above.)
.PP
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
\fIPKZIP\fP 2.04g uses the OEM code page; Windows \fIPKZIP\fP 2.50 uses
Latin-1 (and is therefore incompatible with DOS \fIPKZIP\fP); Info-ZIP uses
the OEM code page on DOS, OS/2 and Win3.x ports but Latin-1 everywhere
else; and Nico Mak's \fIWinZip\fP 6.x does not allow 8-bit passwords at all.
\fIUnZip\fP 5.3 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.  (Since there are no known archivers that encrypt
using EBCDIC encoding, EBCDIC is not tested on non-EBCDIC systems.)  ISO
character encodings other than Latin-1 are not supported.
.PD
.\" =========================================================================
.SH EXAMPLES
To use \fIunzip\fP to extract all members of the archive \fIletters.zip\fP
into the current directory and subdirectories below it, creating any
subdirectories as necessary:
.PP
.Y "unzip letters"
.PP
To extract all members of \fIletters.zip\fP into the current directory only:
.PP
.Y "unzip -j letters"
.PP
To test \fIletters.zip\fP, printing only a summary message indicating
whether the archive is OK or not:
.PP
.Y "unzip -tq letters"
.PP
To test \fIall\fP zipfiles in the current directory, printing only the
summaries:
.PP
.Y "unzip -tq \e*.zip"
.PP
(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
\fIletters.zip\fP whose names end in \fI.tex\fP, auto-converting to the
local end-of-line convention and piping the output into \fImore\fP(1):
.PP
.Y "unzip \-ca letters \e*.tex | more"
.PP
To extract the binary file \fIpaper1.dvi\fP to standard output and pipe it
to a printing program:
.PP
.Y "unzip \-p articles paper1.dvi | dvips"
.PP
To extract all FORTRAN and C source files--*.f, *.c, *.h, and Makefile--into
the /tmp directory: