HP360LX search through txt file

Hi,

Looking for any suggestions about the following problem.

My old 200lx died on me and i've bought a 360lx as replacement.
I need to search a .txt file for partnumbers.
The structure of the txt file is like this

123abcd
123abdgf
456jhtgd

and so on for about 10.000 entries.

What I want the 360LX to do is when I enter a partnumber it searches the file for a match.
If a match is found it shows me something like 'partnumber found in file' if not it just waits for the next number to be introduced.
I can't use the search function in word on the machine because that's way to slow, need a prog where I can introduce number after number at a descent rate.
The old 200lx did a very good DOS job with that but under Windows CE I'm lost.