unzip.1

压缩算法的源代码

.\" Info-ZIP grants permission to any individual or institution to use, copy,
.\" or redistribute this software, so long as:  (1) all of the original files
.\" are included; (2) it is not sold for profit; and (3) this notice is re-
.\" tained.
.\"
.\" unzip.1 by Greg Roelofs, Fulvio Marino, Jim van Zandt and others.
.\"
.\" =========================================================================
.\" define .Y macro (for user-command examples; normal Courier font):
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..
.\" =========================================================================
.TH UNZIP 1L "28 Aug 94 (v5.12)"
.SH NAME
unzip \- list, test and extract compressed files in a ZIP archive
.PD
.\" =========================================================================
.SH SYNOPSIS
\fBunzip\fP [\fB\-Z\fP] [\fB\-cflptuvz\fP[\fBabjnoqsCLV$\fP]]
\fIfile\fP[\fI.zip\fP] [\fIfile(s)\fP\ .\|.\|.]
[\fB\-x\fP\ \fIxfile(s)\fP\ .\|.\|.] [\fB\-d\fP\ \fIexdir\fP]
.PD
.\" =========================================================================
.SH DESCRIPTION
\fIunzip\fP 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, \fIzip\fP(1L), creates ZIP 
archives; both programs are compatible with archives created by PKWARE's 
\fIPKZIP\fP and \fIPKUNZIP\fP for MS-DOS, but in many cases the program 
options or default behaviors differ.
.PD
.\" =========================================================================
.SH ARGUMENTS
.TP
.IR 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 Unix \fIegrep\fP(1)
(regular) expressions and may contain:
.RS
.IP *
matches a sequence of 0 or more characters
.IP ?
matches exactly 1 character
.IP [.\|.\|.]
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 \fIexcept\fP
the characters inside the brackets is considered a match).
.RE
.IP
(Be sure to quote any character which 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 \fC.zip\fP is appended.  Note that 
self-extracting ZIP files are supported, as with any other ZIP archive;
just specify the \fC.exe\fP suffix (if any) explicitly.
.IP [\fIfile(s)\fP]
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 \fB\-v\fP in \fBOPTIONS\fP 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.
.IP [\fB\-x\fP\ \fIxfile(s)\fP]
An optional list of archive members to be excluded from processing.
Since wildcard characters match directory separators (`/'), this option
may be used to exclude any files which are in subdirectories.  For
example, ``\fCunzip foo *.[ch] -x */*\fR'' would extract all C source files
in the main directory, but none in any subdirectories.  Without the \fB\-x\fP
option, all C source files in all directories within the zipfile would be
extracted.
.IP [\fB\-d\fP\ \fIexdir\fP]
An optional directory to which to extract files.  By default, all files
and subdirectories are recreated in the current directory; the \fB\-d\fP
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 immediately after the
zipfile specification, or between the \fIfile(s)\fP and the \fB\-x\fP
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,
``\fC\-d\ ~\fR'' (tilde) is expanded by Unix C shells into the name 
of the user's home directory, but ``\fC\-d~\fR'' is treated as a
literal subdirectory ``\fB~\fP'' of the current directory.
.\" =========================================================================
.SH OPTIONS
Note that, in order to support obsolescent hardware, \fIunzip\fP's usage
screen is limited to 22 or 23 lines and should therefore be considered a
reminder of the basic \fIunzip\fP syntax rather than an exhaustive list
of all possible flags.
.TP
.B \-Z
\fIzipinfo\fP(1L) mode.  If the first option on the command line is \fB\-Z\fP,
the remaining options are taken to be \fIzipinfo\fP(1L) options.  See the
appropriate manual page for a description of these options.
.TP
.B \-c
extract files to stdout/screen (``CRT'').  This option is similar to the
\fB\-p\fP option except that the name of each file is printed as it is
extracted, the \fB\-a\fP option is allowed, and ASCII-EBCDIC conversion
is automatically performed if appropriate.  This option is not listed in
the \fIunzip\fP usage screen.
.TP
.B \-f
freshen existing files, i.e., extract only those files which
already exist on disk and which are newer than the disk copies.  By
default \fIunzip\fP queries before overwriting, but the \fB\-o\fP 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 
\fB\-f\fP and \fB\-u\fP 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) 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'').
.TP
.B \-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.  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 \fB\-L\fP option was given, the filename is converted to lowercase 
and is prefixed with a caret (^).
.TP
.B \-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).
.TP
.B \-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.
.TP
.B \-u
update existing files and create new ones if needed.  This option performs
the same function as the \fB\-f\fP option, extracting (with query) files
which are newer than those with the same name on disk, and in addition it
extracts those files which do not already exist on disk.  See \fB\-f\fP 
above for information on setting the timezone properly.
.TP
.B \-v
be verbose or print 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, \fB\-v\fP
lists archive files verbosely, adding to the \fB\-l\fP info the compression 
method, compressed size, compression ratio and 32-bit CRC.  When no zipfile
is specified (that is, the complete command is simply ``\fCunzip -v\fR''), a
diagnostic screen is printed.  In addition to the normal header with release
date and version, \fIunzip\fP 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 which might affect the program's operation (see also
\fBDECRYPTION\fP below); and any options stored in environment variables 
which might do the same (see \fBENVIRONMENT OPTIONS\fP below).  As a
modifier it works in conjunction with other options (e.g., \fB\-t\fP) to
produce more verbose or debugging output; this is not yet fully implemented
but will be in future releases.
.TP
.B \-z
display only the archive comment.
.PD
.\" =========================================================================
.SH MODIFIERS
.TP
.B \-a
convert text files.  Ordinarily all files are extracted exactly as they
are stored (as ``binary'' files).  The \fB\-a\fP option causes files identified
by \fIzip\fP as text files (those with the `t' label in \fIzipinfo\fP
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 \fIzip\fP's identification of text files is by no means perfect; some
``text'' files may actually be binary and vice versa.  \fIunzip\fP therefore
prints ``\fC[text]\fR'' or ``\fC[binary]\fR'' as a visual check for each file 
it extracts when using the \fB\-a\fP option.  The \fB\-aa\fP option forces 
all files to be extracted as text, regardless of the supposed file type.
.TP
.B \-b
treat all files as binary (no text conversions).  This is a shortcut for
\fB\-\-\-a\fP.
.TP
.B \-C
match filenames case-insensitively.  \fIunzip\fP's philosophy is ``you get
what you ask for'' (this is also responsible for the \fB\-L\fP/\fB\-U\fP 
change; see the relevant options below).  Because some filesystems are fully
case-sensitive (notably those under the Unix operating system) and because
both ZIP archives and \fIunzip\fP itself are portable across platforms,
\fIunzip\fP's default behavior is to match both wildcard and literal filenames
case-sensitively.  That is, specifying ``\fCmakefile\fR'' on the command line
will \fIonly\fP 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 \fB\-C\fP option may be used to force all filename matches to be 
case-insensitive.  In the example above, all three files would then match 
``\fCmakefile\fR'' (or ``\fCmake*\fR'', or similar).  The \fB\-C\fP option
affects files in both the normal file list and the excluded-file list (xlist).
.TP
.B \-j
junk paths.  The archive's directory structure is not recreated; all files
are deposited in the extraction directory (by default, the current one).
.TP
.B \-L
convert to lowercase any filename originating on an uppercase-only operating 
system or filesystem.  (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 
filesystems (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 
filesystem 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 \-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 which 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 \-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.)
.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 which 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;##\fP.  By default the ``\fC;##\fR'' version 
numbers are stripped, but this option allows them to be retained.  (On 
filesystems which limit filenames to particularly short lengths, the version 
numbers may be truncated or stripped regardless of this option.)
.TP
.B \-X
[VMS] restore owner/protection info (may require system privileges).  Ordinary
file attributes are always restored, but this option allows UICs to be restored
as well.  [The next version of \fIunzip\fP will support Unix UID/GID info as 
well, and possibly NT permissions.]
.TP
.B \-$
[MS-DOS, OS/2, NT, Amiga] 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:
.LP
.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
.LP
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
.LP
.Y "unzip \-\-q[\fIother options\fC] zipfile"
.LP