[NTLUG:Discuss] Linux script question

[Pervaz Allaudin]

OK I have another linux command question.

I have multiple files in multiple dirs. under a dir. from which I want 
to replace a word and then written back; Either in the same files or 
another dir. as root.

I got till

find src -iname *.ext | xargs sed /oldtext/newtext/

but I cannot get it to write to corresponding files (in the same dire or 
another).

Also another problem I am having is it won't replace the text if I have 
like oldtext.sometext which I need to change to newtext.sometext

I would appreciate some help with this and also would not mind some net 
sources to learn and/or lookup things like this. The two linux books I 
have are basic and inadequate.

Thanks in advance.

Pervaz