their own spe‐
cialized compression methods). By default, zip does not compress
files with extensions in the list .Z:.zip:.zoo:.arc:.lzh:.arj.
Such files are stored directly in the output archive. The envi‐
ronment variable ZIPOPT can be used to change the default op‐
tions. For example under Unix with csh:
setenv ZIPOPT "‐n .gif:.zip"
To attempt compression on all files, use:
zip ‐n : foo
The maximum compression option -9 also attempts compression on
all files regardless of extension.
On Acorn RISC OS systems the suffixes are actually filetypes (3
hex digit format). By default, zip does not compress files with
filetypes in the list DDC:D96:68E (i.e. Archives, CFS files and
PackDir files).
-nw
--no‐wild
Do not perform internal wildcard processing (shell processing of
wildcards is still done by the shell unless the arguments are es‐
caped). Useful if a list of paths is being read and no wildcard
substitution is desired.
-N
--notes
[Amiga, MacOS] Save Amiga or MacOS filenotes as zipfile comments.
They can be restored by using the ‐N option of unzip. If ‐c is
used also, you are prompted for comments only for those files
that do not have filenotes.
-o
--latest‐time
Set the "last modified" time of the zip archive to the latest
(oldest) "last modified" time found among the entries in the zip
archive. This can be used without any other operations, if de‐
sired. For example:
zip ‐o foo
will change the last modified time of foo.zip to the latest time
of the entries in foo.zip.
-O output‐file
--output‐file output‐file
Process the archive changes as usual, but instead of updating the
existing archive, output the new archive to output‐file. Useful
for updating an archive without changing the existing archive and
the input archive must be a different file than the output
archive.
This option can be used to create updated split archives. It can
also be used with -U to copy entries from an existing archive to
a new archive. See the EXAMPLES section below.
Another use is converting zip files from one split size to an‐
other. For instance, to convert an archive with 700 MB CD splits
to one with 2 GB DVD splits, can use:
zip ‐s 2g cd‐split.zip ‐‐out dvd‐split.zip
which uses copy mode. See -U below. Also:
zip ‐s 0 split.zip ‐‐out unsplit.zip
will convert a split archive to a single‐file archive.
Copy mode will convert stream entries (using data descriptors and
which should be compatible with most unzips) to normal entries
(which should be compatible with all unzips), except if standard
encryption was used. For archives with encrypted entries, zip‐
cloak will decrypt the entries and convert them to normal en‐
tries.
-p
--paths
Include relative file paths as part of the names of files stored
in the archive. This is the default. The -j option junks the
paths and just stores the names of the files.
-P password
--password password
Use password to encrypt zipfile entries (if any). THIS IS INSE‐
CURE! Many multi‐user operating systems provide ways for any
user to see the current