unzip/man/funzip.1

.\"  Copyright (c) 1990-2009 Info-ZIP.  All rights reserved.
.\"
.\"  See the accompanying file LICENSE, version 2009-Jan-02 or later
.\"  (the contents of which are also included in unzip.h) for terms of use.
.\"  If, for some reason, all these files are missing, the Info-ZIP license
.\"  also may be found at:  ftp://ftp.info-zip.org/pub/infozip/license.html
.\"
.\" funzip.1 by Greg Roelofs and others.
.\"
.\" =========================================================================
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.\" =========================================================================
.TH FUNZIP 1 "20 April 2009 (v3.95)" "Info-ZIP"
.SH NAME
funzip \- filter for extracting from a ZIP archive in a pipe
.PD
.SH SYNOPSIS
\fBfunzip\fP [\fB\-password\fP] [\fIinput[.zip|.gz]\fP]
.\" =========================================================================
.SH ARGUMENTS
.IP [\fI\-password\fP]
Optional password to be used if ZIP archive is encrypted.  Decryption
may not be supported at some sites.  See DESCRIPTION for more details.
.IP [\fIinput[.zip|.gz]\fP]
Optional input archive file specification. See DESCRIPTION for details.
.PD
.\" =========================================================================
.SH DESCRIPTION
.I funzip
without a file argument acts as a filter; that is, it assumes that a
ZIP archive (or a \fIgzip\fP'd(1) file) is being piped into
standard input, and it extracts the first member from the archive to stdout.
When stdin comes from a tty device,
.I funzip
assumes that this cannot be a stream of (binary) compressed data and
shows a short help text, instead.
If there is a file argument, then input is read from the specified file
instead of from stdin.
.PP
A password for encrypted zip files can be specified
on the command line (preceding the file name, if any) by prefixing the
password with a dash.  Note that this constitutes a security risk on many
systems; currently running processes are often visible via simple commands
(e.g., \fIps\fP(1) under Unix), and command-line histories can be read.
If the first entry of the zip file is encrypted and
no password is specified on the command line, then the user is prompted for
a password and the password is not echoed on the console.
.PP
Given the limitation on single-member extraction, \fIfunzip\fP is most
useful in conjunction with a secondary archiver program such as \fItar\fP(1).
The following section includes an example illustrating this usage in the
case of disk backups to tape.
.PD
.\" =========================================================================
.SH EXAMPLES
To use \fIfunzip\fP to extract the first member file of the archive test.zip
and to pipe it into \fImore\fP(1):
.PP
.EX
funzip test.zip | more
.EE
.PP
To use \fIfunzip\fP to test the first member file of test.zip (any errors
will be reported on standard error):
.PP
.EX
funzip test.zip > /dev/null
.EE
.PP
To use \fIzip\fP and \fIfunzip\fP in place of \fIcompress\fP(1) and
\fIzcat\fP(1) (or \fIgzip\fP(1) and \fIgzcat\fP(1)) for tape backups:
.PP
.EX
tar cf \- . | zip \-7 | dd of=/dev/nrst0 obs=8k
dd if=/dev/nrst0 ibs=8k | funzip | tar xf \-
.EE
.PP
(where, for example, nrst0 is a SCSI tape drive).
.PD
.\" =========================================================================
.SH BUGS
When piping an encrypted file into \fImore\fP and allowing \fIfunzip\fP
to prompt for password, the terminal may sometimes be reset to a non-echo
mode.  This is apparently due to a race condition between the two programs;
\fIfunzip\fP changes the terminal mode to non-echo before \fImore\fP reads
its state, and \fImore\fP then ``restores'' the terminal to this mode before
exiting.  To recover, run \fIfunzip\fP on the same file but redirect to
/dev/null rather than piping into more; after prompting again for the
password, \fIfunzip\fP will reset the terminal properly.
.PP
There is presently no way to extract any member but the first from a ZIP
archive.  This would be useful in the case where a ZIP archive is included
within another archive.  In the case where the first member is a directory,
\fIfunzip\fP simply creates the directory and exits.
.PP
The functionality of \fIfunzip\fP should be incorporated into \fIunzip\fP
itself (future release).
.PD
.\" =========================================================================
.SH "SEE ALSO"
\fIgzip\fP(1), \fIunzip\fP(1), \fIunzipsfx\fP(1), \fIzip\fP(1),
\fIzipcloak\fP(1), \fIzipinfo\fP(1), \fIzipnote\fP(1), \fIzipsplit\fP(1)
.PD
.\" =========================================================================
.SH URL
The Info-ZIP home page is currently at
.EX
\fChttp://www.info-zip.org/pub/infozip/\fR
.EE
or
.EX
\fCftp://ftp.info-zip.org/pub/infozip/\fR .
.EE
.PD
.\" =========================================================================
.SH AUTHOR
Mark Adler (Info-ZIP)