[gentoo-user] Multi-file search & replace of text

[Stroller]

Hi there,

If I want to automagically replace text in a file, I can use `sed`. I don't believe that `sed` can be invoked in such a way to change the file in place, therefore two commands are necessary:

   $ sed 's/Project Gutenberg/Wordsworth Classics/' foo > bar
   $ mv bar foo 
   $ 

Using `grep` I can search *recursively* through directories to find the text I'm looking for. EG: `grep -R Gutenberg ~`

I would like to find every instance of $foo in a directory hierarchy and replace it with $bar. 

Is there any tool that will combine all these operations for me?

If not, what is the best way to string together grep and sed so that they'll do what I want?

Many thanks for reading,

Stroller.