Tribblix: manual page: funzip.1

FUNZIP(1L) FUNZIP(1L)

NAME

funzip - filter for extracting from a ZIP archive in a pipe

SYNOPSIS

funzip [-password] [input[.zip|.gz]]

ARGUMENTS

[-password]
Optional password to be used if ZIP archive is encrypted.
Decryption may not be supported at some sites. See
DESCRIPTION for more details.

[input[.zip|.gz]]
Optional input archive file specification. See DESCRIPTION for
details.

DESCRIPTION

funzip without a file argument acts as a filter; that is, it assumes
that a ZIP archive (or a gzip'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, 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.

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., ps(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.

Given the limitation on single-member extraction, funzip is most
useful in conjunction with a secondary archiver program such as
tar(1). The following section includes an example illustrating this
usage in the case of disk backups to tape.

EXAMPLES

To use funzip to extract the first member file of the archive
test.zip and to pipe it into more(1):

funzip test.zip | more

To use funzip to test the first member file of test.zip (any errors
will be reported on standard error):

funzip test.zip > /dev/null

To use zip and funzip in place of compress(1) and zcat(1) (or
gzip(1L) and gzcat(1L)) for tape backups:

tar cf - . | zip -7 | dd of=/dev/nrst0 obs=8k
dd if=/dev/nrst0 ibs=8k | funzip | tar xf -

(where, for example, nrst0 is a SCSI tape drive).

BUGS

When piping an encrypted file into more and allowing funzip 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;
funzip changes the terminal mode to non-echo before more reads its
state, and more then ``restores'' the terminal to this mode before
exiting. To recover, run funzip on the same file but redirect to
/dev/null rather than piping into more; after prompting again for the
password, funzip will reset the terminal properly.

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, funzip simply creates the directory and exits.

The functionality of funzip should be incorporated into unzip itself
(future release).

URL

The Info-ZIP home page is currently at
http://www.info-zip.org/pub/infozip/
or
ftp://ftp.info-zip.org/pub/infozip/ .

AUTHOR

Mark Adler (Info-ZIP)

Info-ZIP 20 April 2009 (v3.95) FUNZIP(1L)