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1993-07-22
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╔═══════════════╗
║ HEXED ║
║ Hex Editor! ║
║By Nigel Grange║
╚═══════════════╝
Introduction
============
Welcome to HEXED, an easy to use hex editor. Any file of any type may be
edited in any way, and HEXED also comes with a number of useful tools to
aid editing.
Although there are quite a few file editors around, I hope you'll find
this one of the easiest to use. It's also completely free, which can
only make it even better!
Loading HEXED
=============
HEXED may be started by typing HEXED at the DOS command prompt, followed
by the name of the file you wish to edit. For example, if you wish to
take a look at a file called DATA.DAT, simply type HEXED DATA.DAT at the
DOS prompt. If there were any problems, HEXED will tell you. When the
file has been loaded, a backup will be taken, just in case you do
something wrong, and the main HEXED screen will be shown.
The HEXED Screen
================
The HEXED screen shows a large amount of information, which may seem
daunting at first, but is extremely simple to use. The centre of the
screen shows a hex listing of the file you typed at the command prompt.
The left hand side of the hex listing shows the address of the start of
the current line, in hexadecimal. The first line should read 0000:0000,
indicating the start of the file. These numbers range from 0000:0000 to
FFFF:FFF0, allowing even the largest of files to be edited using HEXED.
The centre of the hex listing shows in hexadecimal each byte of the
section of the file you are currently viewing. The first byte of the
first line (the first byte in the file) should be highlighted in red. On
the right hand side of the hex listing is an display equivalent to the
centre, but the information is displayed in ASCII characters instead of
hexadecimal numbers. Values out of the range 32-127 will be replaced by
a '.', for clarity. The first byte of the first line will also be
highlighted, this time in blue. The red and blue highlights represent
the cursor and show which byte in the file is currently available for
editing. This cursor may be moved around the screen by using the arrow
keys. If the cursor goes beyond the top or bottom of the hex listing,
the display will scroll up and down automatically. Try it and see!
The very top of the screen displays a title so you know whose file
editor you are using. The bottom of the screen displays a number of
items. The main part is taken up by a menu. I'll explain this in a
moment. To the right of the menu is an arrow pointing to the left, and
beyond that, an 8-digit hexadecimal number. This number is the address
of the byte under the cursor. It will start at 0000:0000, and adjust
itself when the cursor is moved. Try this and see!
HEXED Controls
==============
I've already explained how to use the cursor keys to move the cursor
around the hex listing, and how to scroll it up and down by moving the
cursor to the top or bottom of the hex listing. However, there are
numerous other keys to make life easier. PAGE UP and PAGE DOWN will move
the hex listing up and down respectively a page at a time. The cursor
will stay in the same place on the screen. HOME will move the cursor to
the first byte in the file, and END will position it on the last byte of
the file.
The TAB key is very important, and is used to switch modes. When first
started, HEXED will display a red cursor in the hexadecimal listing, and
a blue cursor in the ASCII listing. When you press the TAB key, the
colours will switch, and the small arrow on the bottom line will point
to the right. Pressing the TAB key again will switch the colours again,
and the small arrow will point to the left again. What is the
significance of this? Switching modes tells HEXED which type of data you
wish to edit. Initially, you are in HEX MODE, and are able to edit the
hexadecimal data directly. When you switch modes with the TAB key, you
are in TEXT MODE, and are able to edit the ASCII text directly. You can
identify which mode you are in by two methods. Firstly, by the colour of
the cursor. The red cursor is always over the data to be edited, so if
the red cursor is over the ASCII text, you are in text mode. The blue
cursor is a trace, and is used to trace the position of the true cursor
in the other set of data. This may sound complex, but is very easy to
use. The second way is by looking at the arrow on the bottom line. If it
is pointing to the left, you are in HEX MODE, if it is pointing to the
right, you are in TEXT MODE.
On top of the these controls, there are functions attached to the F-
keys. The functions of these are displayed on the bottom line, and will
be explained shortly.
Editing Data
============
Data may be edited in one of two ways, depending on the mode you are
currently in.
HEX MODE: When you are in hex mode, typing a hex digit (0-F) will
display the current address on the bottom line together with the digit
you typed. If you then press a second hex digit, the current location
will change to the hex number you entered, and the ASCII display will
change to reflect this. The cursor will then move to the next byte in
the file. If you do not type a hex digit for the second input, the
function will be cancelled.
TEXT MODE: When in text mode, simply typing any characters in the range
32-127 (all characters accessible on a normal keyboard) will set the
byte at the current position to the value entered. The cursor will move
to the next byte as usual.
You may have noticed that when using the cursor keys to scroll down
through the file, you were able to scroll past the end of the file. When
this happens, the listing fills with lines of zeros, to show that there
is no more data available. Pressing the END key will take you back up to
the end of the file. However, you will still be able to enter data as in
any other part of the file, and if you do so, the file will be extended
to take account of this. This feature allows you to easily append
information to a file.
Function Keys
=============
The menu at the bottom of the screen displays a list of six functions:
F1 - Find
F2 - Safety Mode On/Off
F3 - Convert
F4 - Save
F5 - Re-Load
F6 - Goto
F1 - FIND
=========
This function is used to find a sequence of bytes in the current file.
It operates in two ways, depending upon the mode you are currently in.
HEX MODE: You will be prompted for a sequence of hex digits. When you
press ENTER, the file will be searched from the current position until
the sequence is found. If it is found, the computer will beep and the
cursor will move to the first byte of the sequence. When entering the
hex digits, enter them as a single line, with no breaks in between. For
example, if you wish to search for the hex bytes AB CD EF in that order,
simply type ABCDEF. If you just press ENTER without entering anything,
the last search will be repeated, providing it was done in hex mode.
TEXT MODE: You will again be prompted for a sequence of characters to
search for. All characters entered will be displayed in capital letters,
but the search will look for characters of either capital or lower case.
This aids in searching for words when the case is not known, or contains
mixed capital and lower case letters. If ENTER is pressed without
entering anything, the previous search will be performed, providing it
was done in TEXT MODE.
F2 - SECURITY MODE ON/OFF
=========================
This command turns the security mode on or off. Security mode is only
operational when in text mode. When security is on, characters will only
be allowed to be entered over existing characters in the range 32-127.
That is, you will be prevented from overwriting anything not in the
range 32-127. This prevents overwriting most program code, and any end-
of-string characters.
F3 - CONVERT
============
This command is a useful tool, allowing you to convert between decimal
and hexadecimal. When you press F3, you will be presented with a menu
giving you the choice of either decimal to hexadecimal conversion (F1)
or hexadecimal to decimal conversion (F2). Press the appropriate key,
then enter either a decimal or hexadecimal number, as prompted. Decimal
numbers will only be allowed in the range that can be represented by an
eight digit hexadecimal number (0-4,294,967,295).
F4 - SAVE
=========
This command will save all of the current changes to the file so far.
There is no going back, so make sure you are happy with the file.
F5 - RE-LOAD
============
This command will re-load the file from the last time you saved it. If
no saved have been done, this command will restore the file completely.
There is no recovering your changes after this command, so only use it
when you have made a genuine mistake.
F6 - GOTO
=========
This command allows you to move the cursor to any position within the
file. You will be prompted for a hexadecimal offset from the beginning
of the file.
This concludes the documentation for HEXED and I hope you find the
program useful. If there are one or two more features that you would
like to see included, drop me a note, plus £10 for my effort, and I'll
send you an updated version of the program with your requests fulfilled.
(£10 is pretty cheap for programming-on-request!)
You can contact me at:
22 Osmond Gardens,
Wallington,
Surrey.
SM6 8SU.
UK.
I'm not rich enough to own a modem, so there's no other contact methods.
Sorry.
Please make all cheques payable to Nigel Grange.
DISCLAIMER: Neither I nor Future Publishing are responsible for any
damage that this program may or may not cause. This program could very
easily damage a file, so make sure you know what you're doing before
trying anything. (Try out the program on a file you don't want anymore
to get the hang of all of the functions). I've given you the
instructions, so don't go blaming anyone but yourself if things go
wrong. This program is bug free (I think) so it won't intentionally
damage any of your files, but it's probably best to back up a file
before hand, just in case your fingers slip...