Section: Misc. Reference Manual Pages (1L)
Updated: 20 April 2009 (v3.95)
funzip - filter for extracting from a ZIP archive in a pipe
Optional password to be used if ZIP archive is encrypted. Decryption
may not be supported at some sites. See DESCRIPTION for more details.
Optional input archive file specification. See DESCRIPTION for details.
without a file argument acts as a filter; that is, it assumes that a
ZIP archive (or a gzip
(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,
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.
To use funzip
to extract the first member file of the archive test.zip
and to pipe it into more
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).
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;
changes the terminal mode to non-echo before more
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
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).
The Info-ZIP home page is currently at
Mark Adler (Info-ZIP)