Hex Editing Query(Technical Question)

[sid_19840]

I have always had this doubt in my mind,

What is a hex editor,what kind of files can it be used on?

What are the different hex values,what do you mean by opcodes?

What do the different numbers in hex editing mean?

Any answers on these questions would be appreciated.

Siddharth(sid_19840)


EDIT-Forgot to ask this question:Where can i find good guides or tutorials in the web on hexediting.

 

[Kev]

Hex editors can be used for editing most files. As computers store information in Binary format (1's and 0's only) this is difficult to read, Hexadecimal allows easier editing as its easier to read. To get the most out of hex editing you need to understand machine code but they can be most useful for editing text from within a file.

 

[sid_19840]

What is machine code?

Also some of my initial questions remain unanswered.

 

[Kev]

Machine code is the commands the CPU uses to carry out operations. Most programs are written in a programming language such as C++ as these convert the machine code into a more readable language.

In answer to your question what are hex codes, hex is just another way of repesenting numbers ie

the number 42 (in decimal) is 101010 in binary and 2A in hex

 

[sid_19840]

I see,why do we need a hexeditor then,can we just change them using a normal tool.

Also what are the basics of hexediting,how do I know what to edit during hexediting?

 

[Kev]

what do you mean a normal tool?

Its very difficult to use a hex editor fully as you are looking at the pure code of the file. Normally a hex editor will show the Hex and Ascii representation of the same code, in this way you can see text within the file and edit it.

 

[sid_19840]

Thanks ill just repeat the questions that ive still not got answers on

What are the basics of hexediting,and where can i learn them?

What are opcodes?

Also ill just add a ques on a term i saw in a different thread

What is an assembly language?(I saw this in c2k5 thread somewhere that only sam knows assembly language)

 

[Kev]

Sorry, cant answer all your questions, maybe you should try using a search engine, there are plenty of tech forums out there which can answer you better than me.

 

[Prakash]

Here try looking at these http://en.wikipedia.org/wiki/Hex_editor and http://en.wikipedia.org/wiki/Assembly_language . And also don't forget about www.google.com !

 

[sid_19840]

ok,thanks.

 

[ashu2411]

Here try looking at these http://en.wikipedia.org/wiki/Hex_editor and http://en.wikipedia.org/wiki/Assembly_language . And also don't forget about www.google.com !

thanks prakash you are always very helpful
Ashutosh Garg