therefore
prints ‘‘[text]’’ or ‘‘[binary]’’ as a visual check for each file
it extracts when using the -a option. The -aa option forces all
files to be extracted as text, regardless of the supposed file
type. On VMS, see also -S.
-b [general] treat all files as binary (no text conversions). This
is a shortcut for ---a.
-b [Tandem] force the creation files with filecode type 180 (’C’)
when extracting Zip entries marked as "text". (On Tandem, -a is
enabled by default, see above).
-b [VMS] auto‐convert binary files (see -a above) to fixed‐length,
512‐byte record format. Doubling the option (-bb) forces all
files to be extracted in this format. When extracting to standard
output (-c or -p option in effect), the default conversion of
text record delimiters is disabled for binary (-b) resp. all
(-bb) files.
-B [when compiled with UNIXBACKUP defined] save a backup copy of
each overwritten file. The backup file is gets the name of the
target file with a tilde and optionally a unique sequence number
(up to 5 digits) appended. The sequence number is applied when‐
ever another file with the original name plus tilde already ex‐
ists. When used together with the "overwrite all" option -o,
numbered backup files are never created. In this case, all backup
files are named as the original file with an appended tilde, ex‐
isting backup files are deleted without notice. This feature
works similarly to the default behavior of emacs(1) in many loca‐
tions.
Example: the old copy of ‘‘foo’’ is renamed to ‘‘foo~’’.
Warning: Users should be aware that the ‐B option does not pre‐
vent loss of existing data under all circumstances. For example,
when unzip is run in overwrite‐all mode, an existing ‘‘foo~’’
file is deleted before unzip attempts to rename ‘‘foo’’ to
‘‘foo~’’. When this rename attempt fails (because of a file
locks, insufficient privileges, or ...), the extraction of
‘‘foo~’’ gets cancelled, but the old backup file is already lost.
A similar scenario takes place when the sequence number range for
numbered backup files gets exhausted (99999, or 65535 for 16‐bit
systems). In this case, the backup file with the maximum se‐
quence number is deleted and replaced by the new backup version
without notice.
-C use case‐insensitive matching for the selection of archive en‐
tries from the command‐line list of extract selection patterns.
unzip’s philosophy is ‘‘you get what you ask for’’ (this is also
responsible for the -L/-U change; see the relevant options be‐
low). Because some file systems are fully case‐sensitive (no‐
tably those under the Unix operating system) and because both ZIP
archives and unzip itself are portable across platforms, unzip’s
default behavior is to match both wildcard and literal filenames
case‐sensitively. That is, specifying ‘‘makefile’’ on the com‐
mand line will only match ‘‘makefile’’ in the archive, not
‘‘Makefile’’ or ‘‘MAKEFILE’’ (and similarly for wildcard specifi‐
cations). Since this does not correspond to the behavior of many
other operating/file systems (for example, OS/2 HPFS, which pre‐
serves mixed case but is not sensitive to it), the -C option may
be used to force