lclean(1)
NAME
lclean - Detect and clean trash in Structured Storage doc
uments
SYNOPSIS
lclean "-r" || "-c" || "-s" || "-i" || "-l" || "-e" docu
ment
Note! If you use switch "-c" or "-i", lclean changes your
document! Please keep a backup of the treated documents,
until you are sure they did not take any harm!
DESCRIPTION
lclean deals with documents created typically with MS Win
dows applications. It gives a report about the trash sec
tions in those "OLE / Structured Storage" documents,
cleans this trash or saves it to files. Further more a
file can be hidden into and extracted from those trash
sections.
- clean
- lclean "-c" ["-n"] {document}
- The trash sections will be cleaned. Unused blocks are
filled with null bytes. System data will be cleaned
with 0xff bytes. File end trash (type 4) will be
cleaned with random bytes. When using switch "-n",
file end trash also will be filled with zero bytes
(faster on files with lots of embedded objects). - extract
- lclean "-e" ["-f"] ["-z"] {document}
- Extracts the hidden file. This makes a copy of the
hidden file. If the file got corrupted by what reason
ever, it will not be extracted. The file will get the
date of its last modification. If the file already
exists, you will be prompted to overwrite it with the
new extracted file. With switch "-f" you will not be
prompted, but the file will be overwritten. With
switch "-z" no zero length files will be created. - insert
- lclean "-i" <file> ["-a"] {document}
- Insert a file into the document (hide it). The trash
in your document will be substituted by some <file>.
This file cannot be seen by any standard Windows
application. The file must be smaller, than the size
of the trash in your documents (plus 20 bytes plus the
size to store the filename). Normally, only trash
types 1 and 2 will be used for this. If they offer not
enough space, with switch "-a" trash type 4 and 8 will
be used additionally. - list
- lclean "-l" {document}
- List if there is a file hidden in the documents trash.
- report
- lclean "-r" {document}
- Gets a small report about the trash in the documents.
- save
- lclean "-s" ["-a"] ["-d"] ["-z"] {document}
- The trash sections will be saved to own files. They
will be stored to an directory in your current direc
tory. Normally it will be the directory ""doctrash"".
E.g., if there is the example file ""legacy.doc"" the
trashfiles will be stored as: ""doctrash/legacy.tr1"",
""doctrash/legacy.tr2"", ""doctrash/legacy.tr3"" and
""doctrash/legacy.tr4"". - "-a"
All trash will be stored into one big file ""doc
trash/legacy.tra"". - "-d"
The trash file(s) will not be stored into direc
tory ""doctrash"", but each into an own directory.
E.g. into directory ""legacy/"". - "-z"
When using switch "-z", zero length files will not
be created.
EXAMPLES
- lclean "-cs" {document}
- This would first save all trash chunks into separate
files into directory ""doctrash"", then it would clean
the document. - lclean "-aci" <file> {document}
- This would first clean the document, then insert the
hidden file by using all trash types.
HISTORY
Microsoft's first and still most spread OLE implementa
tions had bugs. One caused that some sections of documents
that actually should be filled with zero bytes contained
more or less private data.
Management of OLE documents is a little bit difficult and
takes some time. A way to fasten this up is not to care
about the old data, but simply to add the new data to the
document. Cleaning up could be done later. When switched
on the "fast save" option, Microsoft Word uses this strat
egy. So, thus saved files contain the new and the old
version of a document. The old data cannot be edited any
more and stays invisible in the document.
Some programs seem to use the Microsoft OLE library not
properly. For example, the Star Office 3.1. programs cre
ate documents, that always contain 1024 bytes of trash.
As far as I know, Microsoft offers a bugfix for 32 bit
Windows systems, only.
The program "lclean" can access this kind of garbage in
OLE documents. To do this it uses the "modify_trash"
method of OLE::Storage. This library decides between four
different types of trash.
Overview:
- Type 1
- Unused "big blocks". These blocks are not used by the
document. Each of these blocks is 512 bytes long. - Type 2
- Unused "small blocks". These blocks are not used by
the document. Each of these blocks is 64 bytes long. - Type 4
- File end space. This refers to the "streams" of an OLE
document. The space is made up of all the space
between the end of a stream and the end of a block. - Type 8
- System space. These sections are required by file for
mat, though they are not used by OLE system. Actually
this data is no garbage.
SEE ALSO
OLE::Storage
AUTHOR
- Martin Schwartz <schwartz@cs.tu-berlin.de>.