sed and/or awk could be used for what you want.
Both have many options and can be as complex (or simple) as you want. You should read the man pages, search the net or buy a book about sed and/or awk.
O'Reilly has a good book that covers both (sed & awk)
An on-line awk tutorial/examples:
On-line sed tutorials/examples:
There are a lot more, just feed your searchengine with the appropriate keywords :-)
How you set up your .conf file(s) depends on, among other things:
- is (human)readability important,
- does every user need his/her own .conf file.
I like the 'one line per user' approach. Which also means that you could do with only 1 .conf file. The file will be (a bit) harder to read by humans, but it's a lot easier to work with from a programming point of view (most tools in unix/linux are line driven by default).
Using the one-line-per-user approach your .conf file will look like this (or take a look at the way /etc/passwd is set up):
#username age sex
jake 22 male
jane 25 female
The space is the seperator (which you can change: see /etc/passwd, seperator is ':').
Hope this helps a bit.