Section: User Commands (1)
Updated: 20 April 2009 (v3.95)
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.
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
tar cf - . | zip -7 | dd of=/dev/nrst0 obs=8k dd if=/dev/nrst0 ibs=8k | funzip | tar xf -
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 Info-ZIP home page is currently at
Mark Adler (Info-ZIP)
Tutoriais de Tecnologia Web