I've used the game Ogre Battle on playstation.

We'll begin by using cd-tool in interactive mode.
In order to do so, open a dos prompt (or write the next line in a file with the extension .cmd or .bat)
and write : 
cd-tool -i -w -f filenameoftheiso
-i : interactive mode
-w : write mode (!!important, if you intend to write on the iso!!)

---> ça a beaucoup changé depuis :P Demande à Baha des précisions.

You'll get to the prompt of cd-tool. Here, you can write commands which will be interpreted by the program.
If you've read (even a bit) the cd-tool's documentation, you are familiar with cdutil object.
When you open an iso using the command line, it is represented as 'cdutil'.
So, each time we want to use cd specific classes, the object will be cdutil.

Let's start playing with it !
Write the next line on the prompt, and validate by 'enter' :

path(cdutil)

We get the 'path table' of the iso.
Let's try another thing...
printdir("/",cdutil)

It will write the content of the main directory.
Notice 2 things : 
	-no "\", but "/". This program comes from a linux-die-hard fan. That's why ;)
	----> c'est faux. Les path peuvent être écrits avec des \ sous windows, mais le script ne marchera que sous windows.
	----> mais vu que c'est des strings, il faut du coup faire \\, comme par exemple C:\\AUTOEXEC.BAT
	-every file has ";1" after his name. Don't forget that!!! directories don't have one.

infos(cdutil)

Will show us some...informations ;)

Ok, the introduction is over. Why not trying something more useful :D
We can try to extract a file. Of course, you'd say that it is possible with any iso tool. But sometimes, the file isn't properly extracted (XA stuff), cd-tool handle perfectly this type of files.

We want to extract a file, located at the root of the CD.

extract_file("/NAMEofFile;1","OutputNameOfFile")

Easy, isn't it? It is perfect when you use on XA files (some music & video). Other softwares have difficulties with them...

You can modify it, as you want. Even if the file is bigger than the original one, cd-tool doesn't care :D
To reinsert it, write this : 

insert_file("OutputNameOfFile","/NAMEofFile;1");

No need to rebuild the whole iso, it only took us 1 minute!

To exit the interactive mode, just write 'quit' or 'exit'



Let's try with Ogre Battle.
first, load the iso : 
cd-tool -i -f OB.bin -w

When you start the game, there is a screen with the title of the episode.
[TITLE.png]
After looking on the CD, we found the file with this title.
It is B_TITLE4.TIM. First, we extract it : 

extract_file("/GRP/LOGO/B_TITLE4.TIM;1","EXTRACT/B_TITLE4.TIM");

Then, using your favorite tool, we alter it (I used TIMUTIL).
When we've finished, we want to see how it looks like in-game.
To reinsert it, just write : 

insert_file("EXTRACT/B_TITLE4.TIM","/GRP/LOGO/B_TITLE4.TIM;1");
quit cd-tool ('quit'), and launch any playstation emulator.
[title modified.png]
(I know it is ugly, it was just a test anyway :p )
.
This mode is the easiest one, but useful only for small task, or when you want to discover cd-tool.
The most useful function is the LUA engine.
To know more about LUA, just go to the main website. The main thing you need to know is that LUA is a script language which allows you to write commands interpreted by cd-tool.

For example, we can create a .lua file, write the two functions extract_file and insert_file, and order cd-tool to automatically load theses functions.
how to do it? Just read the second part!

-----
LUA Scripting.

Each script file must contain at least one function.
---> c'est faux :P si un script lua contient juste du code, il sera exécuté aussi sec.
To execute this function, you have to call cd-tool this way :
cd-tool -e main_function() nameofscriptfile.lua
You can add the option '-f nameofiso" if you want to load an iso, and "-w" if you intend to write on the iso.

main_function() is the function of your lua file which will be loaded. It's like main() in C for example.

I've created two .lua files to show you various ways for using LUA with cd-tool.
They are call OB.lua and OB2.lua



slus = cdutil:findpath "/SLUS_004.67;1"
print(slus.id)
  SLUS_004.67;1

First, we start looking at the resources located on the CD. try various tools like Yuri, etc... I will not show you how to find them, it is not the purpose of this guide.

We found the main title image. We'll use cd-tool to extract the file.
extract_file("/GRP/LOGO/B_TITLE4.TIM;1","EXTRACT/B_TITLE4.TIM");

First parameter is the name of the file. Take care of the "/", and of the ";1" at the end of the file.
Second parameter is the location of the extracted file, and its name.

Now, take your favorite TIM editor, and make the necessary modifications.
You know have an altered image, it's time to reinsert it into the iso.

insert_file("EXTRACT/B_TITLE4M.TIM","/GRP/LOGO/B_TITLE4.TIM;1");

And voilà!
It took only 5 minutes to do this.

Le texte d'intro de Warren est dans \GRP\OGOPN\MAKEMSG.DAT