Acorn-specific usage instructions
---------------------------------

As zipfiles can come from a variety of sources apart from Acorn machines,
consideration had to be given to the handling of dot-extensions, a la
DOSFILE.TXT, unix-filename.tar.gz . What was decided that they would
be extracted as DOSFILE/TXT and unix-filename/tar/gz, and then truncated
to 10-characters, for FileCore compliance. This can quickly be altered
for any new releases of FileCore that Acorn may make for longer filenames.
Unfortunately, this means that you must be REALLY careful about
extracting files from archives. The files

    dummy_source.c and dummy_source.h

will both be extracted as

    dummy_sour

UnZip will prompt you for confirmation of the over-writing of these files,
but you must be really careful unless you wish to lose files!
Also, because UnZip is a unix-ported program, the filenames are CASE
SENSITIVE.

    *unzip new/zip newfile

will extract 'newfile', but not 'NewFile', 'NEWFILE' or any other
combinations. However, you can use the -C option to force operations
to disregard the case of filenames.

The Acorn UnZip port has an additional feature to cope with the
extraction of files containing 'c' code. As you may be aware, Acorn
Desktop C requires all files called "foo.c" to be renamed to "c.foo",
ie "foo" in a directory called "c".

To cope with this, a colon-separated environment variable has been
set up called "Unzip$Exts". Any extensions found in this variable will
be extracted to directories named after the extension, with the extension
stripped. For example:

    *Set Unzip$Exts "c:h:o:s"

will extract all the files called 'foo.c' to a directory called 'c'.
This can be used to include "c:h:o:s:txt" to pull all the text files
out to a separate directory.

UnZip fully supports SparkFS Extra Field. This means that zipfiles created
with SparkFS or Zip (on RISC OS) will be correctly unzipped, including
filetypes.

UnZipSFX can be used to create self-extracting archives. To use it, just
create a common zipfile using Zip (or SparkFS), then load the UnZipSFX
executable into an editor (eg. Edit, Zap), go with the caret the end of the
file (using CTRL-CursorDown) and drag the zipfile to the editor window (in
other words, append the zipfile to the UnZipSFX executable). Now, saving the
resulting file (with filetype Absolute (&FF8)), you have a self-extracting
archive (ie. double-clicking on it will unzip the contents of the original
zipfile to the currently selected directory).
