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zap2_5.lzh
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ZAP2_5.TXT
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1985-11-20
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*** Almost Completely Superfluous Manual to ZAP 2.5 ***
*** What is ZAP ? ***
ZAP is an editor, designed to edit program files. That is why it cannot
change the length of a file, and why it displays files both in ASCII
and in hexadecimal code.
It needs very little memory ( less than 25K ) and may be used on files
of arbitrary size, to at least a megabyte.
ZAP is a 'public domain' tool.
Copy it and pass it on as much as you like.
*** Why would I need ZAP ? ***
For any number of reasons. Every time you want to know, and maybe to
change, what is in a file that is not normally readable or printable,
you will find yourself reaching for ZAP.
Other possibilities:
- Use it to change a default path in those irritating programs that
do not know where to find your hard disk or ram disk.
- Use ZAP to modify text in programs of which you do not have the
source code, e.g. to correct spelling mistakes, or to translate
messages.
- Use it to find text in programs, e.g. to look at vocabularies
of games (if they have not been encrypted).
- Use it to look for hidden messages in programs, and experience
the true hacker's thrill....
*** How do I use ZAP ? ***
Very carefully.
ZAP is a like a surgeon's knife: very handy to work with, but dangerous
unless you know exactly what you're doing. As it may take only two
keystrokes in ZAP to ruin any program, one to change a byte and one to
write the changed data back to disk, I must advise you strongly to
ALWAYS make a backup before experimenting. (Not that I ever do. But then
I'm stupid. YOU should know better.)
ZAP, however, also has the possibility to protect a file from changes
on at least four separate levels, to prevent accidental changes.
- If the disk is physically write-protected, or if the file is
read-only, ZAP of course cannot change it.
- If you specify the -r option on the commandline ZAP will not change
the file.
- If you lock the file during editing (click 'r/w' in the EDIT menu)
ZAP will not allow any changes to the file until the lock is switched
off again.
- If you use the text filter, (click 'raw' int the EDIT menu) which
displays only those bytes in the text field which are letters,
digits, or punctuation marks, you cannot modify the file until you
switch the filter off. The reason for this is to ensure that you
write only when you have full information on what you're overwriting.
- If you are in ESC mode ('ESC' displayed in the lower left corner
of the screen) you cannot make changes to the displayed data.
( Note, however, that if you first make changes in EDIT mode, then
switch to ESC mode, then get another chunk, ZAP will write the
modified chunk to disk if you did not lock the file.)
*** Starting ZAP ***
ZAP may be named either ZAP.TTP or ZAP.TOS. It may be double-clicked,
or called from a shell. If a commandline is passed to ZAP, it will be
used, or else it will start with a dialog to ask for a commandline.
In both cases the commandline must be of the same form:
<filename> [ -r ]
where <filename> is any legal TOS path/filename, and the optional
-r (or -R) the read-only option.
Examples: "c:\zap.ttp -r" will open the file ZAP.TTP in read-only mode.
"zap.ttp" will open it normally.
(If the file may be written to in TOS.)
The commandline dialog page also explains how the single-line editor
works. This single-line editor is used also for the search-string
entry, so you may want to remember how it works. Not that there is
anything difficult to it, it's all very logical.
You can move the cursor, use backspace and delete, clear the line
with <Esc> and recall the original line with Undo. Pressing Return
completes input, and if the line is empty ZAP exits.
*So, the way to quit ZAP is to press <Esc> <Return> at the command
line dialog. If the file cannot be opened, or if the commandline
contains the wildcards '*' or '?' ZAP gives an error message and lets
you try again.
*** The ZAP screen ***
This consists of 4 parts: menubar, parameter section, file display,
and command/message line.
The top line is the menu bar. It displays the main command options you
have at your disposal at that point.
There are two menu bars, one for the EDIT mode and one for the ESC mode.
You can see which mode ZAP is in by looking at the lower left corner
of the screen.
In EDIT mode, the menu bar shows:
- ZAP 2.5
The name and version number of the program.
Click this for some info about ZAP and for my address.
- help
Click this (or press <Help>) to get a summary of the workings of
ZAP in edit mode.
- Esc
Click this (or press <Esc>) to switch to ESC mode.
- addr
Click this to jump to an address in the file. This must then be
entered in hexadecimal numbers. The first byte in the file has
address 0, the last byte has address (filesize-1).
- undo
Click this (or press <Undo>) to read the displayed chunk from the
disk into memory again. The situation is now as it was after this
chunk was last saved. This will not affect changes that have already
been saved to disk.
- top
Click this (or press <Shift><Clr Home> ) to get the first chunk.
- ^^^ ( arrows up )
Click this (or press <Shift><up>) to get the previous chunk.
- vvv ( arrows down )
Click this (or press <Shift><down>) to get the next chunk.
- end
Click this (or press <Insert> ) to get the last chunk.
- raw|txt
Click this to toggle the text only filter - useful if you are
scanning a file quickly, looking for text. If the r/w flag was on,
this will be set to r-o (for read-only) until you toggle the text
filter off again.
- r/w|r-o
Click this to lock the file to prevent accidental changes during
browsing, and click it again to unlock it. If the lock is toggled to
unlock, the text filter is automatically switched off too.
*If you attempt to change a file while r-o is in effect, this menu entry
will flash briefly to remind you.
- quit
Click this to save the current chunk and exit to the file selection
dialog page.
In ESC mode, the menu bar shows:
- ZAP 2.5, as above. Here also accessible by pressing Z.
- Help - some info about ESC mode
- UnEsc
Click this, (or press Esc, or press U) to go back to edit mode.
- Print
Click this, (or press P) to print the current chunk. If the text filter
is on, this will be used, otherwise non-printable characters will be
replaced by a hyphen ( '-' ). (Since it is very unlikely that your
printer knows the Atari graphics characters...)
- Number
Click this, (or press N) and you will be asked for a number of the
chunk to display next. This must be entered in decimal.
- Search
Click this (or press S) to enter a string to search for. Depending
on the state of ZAP, you will be asked to enter this string in HEX or
as text. You may use control characters in the text state. In HEX
state, the string must be specified as an even number of hexadecimal
digits. As a null byte is used to terminate the string you can't
search for anything following a null byte. Search is case-sensitive
and starts at the current cursor position.
- Find
Click this (or press F). The same as above, but the search will use
the previously entered string for that state.
- Chunksize
Click this, (or press C), to change the size of a chunk. The default
value, 256, is also the maximum.
- Quit
Click this, (or press Q) to exit to the file selection screen.
Besides these commands you can use the cursor keys and the mouse to
position the cursor and to switch between states. Placing the cursor
in the HEX field with the mouse wil