ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/UTILITY/DISK/CLNFIL23.ZIP/CLEANFIL.DOC

Text File | 1991-02-16 | 17.0 KB | 468 lines

                       C L E A N - F I L E S
                       ═════════════════════

               (c) Copyright 1990,91 by Klaus Hartnegg,
                      D-7835 Teningen, Germany



Description:
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Every time DOS writes a file it fills up the last used cluster with some
randomly collected data. CleanFile wipes out this unused data space
without affecting the file itself. This ensures that you don't
inadvertently publish confidential data when giving away some program-
or data files on diskettes.



New Features?
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If you already have an older version of this program you should at least
read the section 'revision history' near the end of this text.



Requirements
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CleanFile only uses MS-DOS calls to do its work and BIOS for screen
output. It does not use the FAT or any internal data structure of DOS
and should thus run on all types of drives and all versions of DOS from
3.0 on upwards.



Licence
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This software is provided as-is, without warranty of any kind. The
author shall not be liable to the user for any direct, indirect or
consequential loss arising from the use of, or inability to use, any
program or file howsoever caused. No warranty is given that the software
will work under all circumstances.

This software may be distributed free of charge as long as all files
except the key-file are distributed together. The key-file is proof of
your registration and must not be given to other persons.

You may use this program for a 7 day trial period without payment. If
you decide to use it longer than this trial period, you have to pay a
registration fee of $15 (US-$).

The registered version may be used either by one person or on one single
computer only.



Background
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Space on all disks (hard disk or floppy) is split into sectors.
Depending on the size of the disk a sector contains 256, 512 or 1024
characters.  DOS can not write single characters but only complete
sectors. Space on disks used for your files is allocated in even bigger
units: clusters.  A Cluster contains either 2, 4 or 8 sectors.

Very little files happen to need an exact multiple of the cluster size.
When writing a file, DOS fills up the rest of the last sector with some
randomly chosen data that happened to be in one of its internal buffers.
The unused sectors of the last cluster simply retain their previous
content. DOS's internal buffers contain data or disk directories that
you worked on just before.

Imagine what that means: every time you gave a diskette away you
included some private or maybe even confidential data, that you perhaps
didn't really want to publish, even when using a freshly formatted
diskette!

You say `nobody can look at this data'? Oh yes, they can! It's in fact
very easy: there are a lot of programs called `sector editors' that
allow doing exactly this. Perhaps the most popular examples for such
programs are Norton's wonderful utilities NU or DISKEDIT. Of course they
were not written to serve this dubious purpose; instead they are
intended to repair defective disks and do indeed a very good job of
this.



What CleanFile does
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CleanFile overwrites every character that exist beyond the end of your
files with nulls. CleanFile will not only overwrite the rest of the last
sector but also all unneeded sectors in the last cluster. This will not
affect the content of your file.

Please note that CleanFile does not prevent DOS from doing the error
described above. It can only correct the problem after it already
occurred.  Thus it won't help to run CleanFile on the files on your hard
disk that you intend to copy to a disk because the problem arises when
you actually are copying the files. So you'll have to clean all
destination files after every COPY or XCOPY! I am sorry, but that's the
way DOS works!

You may want to use CleanFile not only on diskettes but also on hard
disks when several people share a computer. In this case you will need
an additional program to wipe out the completely unused data space too.




Usage
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Supply the names of the files and/or directories that shall be cleaned
as parameters on the command-line.

You may press Ctrl-Break at any time to abort the processing. CleanFile
will respond with a short beep but will not stop immediately - it has to
close all open files first.


Syntax : CleanFil [/Options] [filename(s)]


filename(s):

   one ore more names of files and/or directories. Filenames may contain
   wildcard characters '?' and '*'. These wildcards will be handled in
   the usual way, NOT like extended wildcards in filenames that you
   supply after the exclude switch (see below)!

   Alternatively CleanFile can read the names of the files and/or
   directories to work on from the standard-input device. To use this
   you should know what redirection of input and output and pipes are.
   Please read your DOS manual for a description of these.


Options:  (Options can be supplied in any order)

/R - recurse into subdirectories (registered versions only!)

   This will cause CleanFil to work not only on the files in the current
   or specified directory but also in all subdirectories and in all
   directories within these subdirectories and so on.


/hid - include hidden files

   Cleanfile will process files with the hidden attribute set only when
   you specify this option. Read the section 'possible problems' below
   before using this option!


/sys - include system files

   Cleanfile will process files with the system attribute set only when
   you specify this option. Read the section 'possible problems' below
   before using this option!


/today - process only files that have been changed today.


/D<date> - process only files that have been changed at or after the
           specified date.

   Run CleanFile without any arguments to find out in which format the
   date has to be written. The format depends on the country for which
   your computer has been installed. If the date format is not what you
   expected then a line is missing or invalid in the file CONFIG.SYS.
   For example in Germany one has to write 'country = 49,437'. No such
   redefinition may be necessary in the USA.


/X<filename> - Exclude all files that match the given filename.

   You can supply many filenames separated by blanks if you put the
   whole string into ' or ". Example: cleanfil *.* '/x*.bak /x*.dat'
   This is however not necessary, because you can as well supply the /x
   switch multiple times. There is only one restriction and this is one
   of DOS not of CleanFile: The whole thing has to fit on the command
   line!

   Please note that the wildcard-handling for the exclude switch is a
   very special one: The names of all found files will be expanded to
   full path names including the drive letter and a colon before checking
   against the supplied filenames to be excluded. The filenames you
   supply may contain wildcard characters: a '?' matches one character
   or nothing, a '*' matches any string. Important: you can include many
   '?' and '*' characters!

   By the way, I said '*' matches ANY STRING. Is '\COMPILER\TP60' a
   string?  YES! So 'c:*\*.pas' will of course match the filename
   'c:\compiler\tp60\cleanfil.pas'!!

   There are two cases handled a bit special to ensure that cleanfile
   always does what you expect. Otherwise these masks would not match
   any file at all:
   1. a mask containing a filename only, no path (i.e. no '\' character)
      will automatically be preceded by '*\'.
   2. a mask starting with '\' will automatically be preceded by '?:'

   Some other examples:

   this pattern  will match
   *\test.*      all files with name 'test'
   *\test*.*     all files with name starting with 'test'
   *\*test*.*    all files with the string 'test' somewhere in the name!
   test.*        (will be translated to *\test.*, see 1st example!)
   *\temp\*.*    all files in all 'temp' directories
   *ler\t*.exe   will for example match 'c:\compiler\tp60\turbo.exe'



/S - simulate only

   This will allow you to become familiar with the way the exclude switch
   is handled without really doing anything. This was included because
   it could cause problems to clean certain files and you should have a
   chance to test whether the excludes you supplied really cause the
   expected files to be excluded. See the section 'possible problems'
   below for more information about such files.

   The program will produce almost the same output, listing all
   processed files, but will say 'ignoring' instead of 'cleaning' and
   will in fact not do anything except opening and closing the files. It
   will NOT really clean the data behind them.



Examples:

"CLEANFILE A:"
   cleans all files in the actual directory on drive A:

"CLEANFILE A:\"
   cleans all files in the root directory of drive A:

"CLEANFILE /r D:\"
   cleans all files on drive D:

"CLEANFILE /r D:\DATA\*.DAT"
   cleans all files ending with "DAT" in directory "D:\DATA" and in all
   directories below

"CLEANFILE C: /r /x*\GAMES\*.*"
   will clean all files on drive C: except the files contained in or
   below a directory with the name "GAMES".

"CLEANFILE <CLEAN.DAT"
   this will read the files to be processed from the file "CLEAN.DAT".
   This file should contain one filename per line.
   The filenames may contain wildcards.



Possible problems
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- Interrupt

  If CleanFile gets interrupted by an external event other than
  Ctrl-Break (for example by a disk error) some files may loose their
  protection flags and will show the wrong (the actual) date and time.
  This is because CleanFile has to remove all protection flags to be
  able to act on write protected files. In addition DOS updates the file
  date and time when CleanFile cleans them. Of course these two effects
  are usually undone by CleanFile before exiting; but when it becomes
  interrupted...


- Output redirection

  When redirecting the screen output of CleanFile to a file please
  ensure that this file will not be cleaned in the same run! I'm working
  on detecting to which file the output is being redirected but
  CleanFile is not yet able to do that. Accessing that file twice could
  cause internal problems in DOS.


- Some copy-protected software

  There exists some brain damaged commercial software that thinks it has
  been illegally copied when the content of the last used sector behind
  the actual end of the file has changed. Possibly they even manipulate
  the directory entry to show less bytes than actually occupied. You
  shouldn't run CleanFile on such software. Please don't blame me when
  you detect such a problem, blame the company that uses this for copy
  protection without placing a warning in the documentation!

  CleanFile now by default skips files with the hidden or system
  attribute set because programs that use such a questionable copy
  protection scheme mostly have one or both of these attributes set. I
  said 'mostly' so please be careful! Sorry, I can't give you any more
  hints on how to identify such software except by looking at these
  flags.

  You may now want to use the exclude switch to process a whole disk
  except some files or directories that could contain such brain damaged
  software. In this case please run cleanfile once with the simulate
  option to make sure that you use the right exclude syntax (the
  enhanced wild card handling is powerful but a bit tricky!). The
  simulate option allows you to see what files will be processed without
  the risk of doing any harm.




A note for unix-users
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This program will accept both
a) '/' and '-' as switch character
b) '\' and '/' as path separator

This can of course cause trouble when you try to start a filename with
'/'. This case will be handled in the following way:

  Usually everything starting with either '-' or '/' will be interpreted
  as an option so you can't start filenames with a '/'.

  When you have set the switch-character to '-' then only this character
  can be used to signal an option and '/' can be used even as the first
  character of a filename!

You can even set the switch character to something completely different,
say '~'. Then you can use both '-' and your switch character ('~')! I
wish every program was so flexible!




Key-File
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Registered users will receive a key-file. This file is proof of your
registration. It contains a serial number, your name and a verification
number. This file, when present, will switch off the registration
reminder and enable some more features.

Without key-file a registration reminder will be shown for 5 seconds
approximately every 3-rd time the program is run. Read the section
"usage" above for more information about the features that are available
for registered users only.

The key-file will be found when it is either in the current directory,
in the same directory as the EXE-file (recommended) or in any other
directory that is contained in your PATH-variable.

The key-file will work with all future versions of this program so you
have to register only once.



Included Files
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CLEANFIL.EXE   executable
CLEANFIL.DOC   documentation
REGISTER.DOC   registration form

CLEANFIL.KEY   key-file (registered version only)



Revision History
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1.0  (sometime in June 1990)

1.1 (July 1990)
- added wildcards
- first official release

1.2 (August 1990)
- bug caused trouble with hidden, read-only and system-files: sometimes
  they grew bigger, sometimes cleanfil aborted.

1.3 (09-10-1990)
- some cosmetic changes (using bios for screen writes now).
- registered version gained even some more speed when working on files
  within a subdirectory
- registration made easier (key-file)

1.3a (09-22-1990)
- several spelling errors corrected in this documentation
- bug caused CleanFile to abort when the key-file was read-only
- CleanFil can now be interrupted with Break or Ctrl-C; it will halt
  execution as soon as it is safe to do so.
- '/' can be used as path separators as well as '\'

1.3b (10-11-1990)
- some more spelling errors
- two bugs when piping filenames into CleanFil: Ctrl-C and the special
  file handling didn't work
- program partly rewritten; using OOP now for special file handling and
  formatted screen output
- fast file handling now available for unregistered users too
- inserted 5 second pause at the start for unregistered users

2.0 (10-16-1990)
- added recursing into subdirectories
- added a section for unix users to this documentation
- output can now be redirected to a file
- improved ctrl-break handler; ctrl-c doesn't work any more, you must
  use ctrl-break. A short beep will signal that the ctrl-break has been
  detected; program execution will stop as soon as possible.
- raised registration fee from $10 to $15, old key-files continue working

2.1 (01-13-1991)
- renamed recursing switch /s to /r
- skipping hidden and system files now by default, also skipping all
  files within directories with one of these attributes set
- added /hid and /sys, use them with care!
- added /today and /D<date>

2.2 (02-08-1991)
- improved screen output handler allows to cross directory boundaries
  in one clean-step thus speeding up a little bit
- added exclude switch using extended wild card handling to exclude
  some files from processing
- added simulate switch

2.3 (02-16-1991)
- the previous version didn't work on XT's


Future plans:
- allow extended wildcards like the ones in excludes in includes too
- skipping file where redirected output is being written to


Many thanks to Michael D. Lawler for beta-testing this program. Large parts
of the above revision history are really a list of suggestions he made.




Registration
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Please register when you decide to use this program longer than the trial
period. I can't continue distributing software in this low cost way if you
do not register!

Print the file REGISTER.DOC, fill out the registration form and send it
to my address below. The registration fee is $15. You can save $5 when
you want your key-file only and can receive uuencoded files via Internet.
Please read the file REGISTER.DOC for details.

Until now I can accept check or money orders only.

Your name and address will be used for creation of the key-file unless
you include a different name (company name or what else).

You will receive the actual versions of all my shareware programs (E2A,
CrLf, StripLf, CleanFil, Config) and your personal key-file for the program
you payed for usually within a few days.


────────────────────────────

   Klaus Hartnegg
   Kleist-str. 7
   D-7835 Teningen
   Germany


This software is under development. Error reports and other comments are
welcome. Please do not hesitate to use electronic mail for communication.

Bitnet   - HAKL@DFRRUF1
Internet - [e-mail]