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funzip − filter for extracting from a ZIP archive in a pipe |
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funzip [−password] [input[.zip|.gz]] |
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[−password] |
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Optional password to be used if ZIP archive is encrypted. Decryption may not be supported at some sites. See DESCRIPTION for more details. |
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[input[.zip|.gz]] |
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Optional input archive file specification. See DESCRIPTION for details. |
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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. |
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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 |
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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 |
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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 − |
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(where, for example, nrst0 is a SCSI tape drive). |
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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). |
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gzip(1L), unzip(1L), unzipsfx(1L), zip(1L), zipcloak(1L), zipinfo(1L), zipnote(1L), zipsplit(1L) |
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The Info-ZIP home page is currently at |
http://www.info-zip.org/pub/infozip/ |
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or |
ftp://ftp.info-zip.org/pub/infozip/ . |
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Mark Adler (Info-ZIP) |