I want a really simple command line script that takes a precedent text file and replaces special tags with specific client data.

The precedent text files will be produced by various programs (including RTF files made by Word).

The information for the clients I'd like to store in files (one file per client) which simply lists the replacements to make.

What scripting language do you think would be quickest/easiest to do this? It seems like such a simple task and yet I'm having problems simply implementing it!