Capture The Keyword From The Log File?

I'm still new in VB.net development environment, i've few of the question may need the advice from you guys to see whether i'm in the right track for the development as below condition:Basically my program wrote from this logics:

Condition:

2 log files available in C drive that is C:/BSKYB/Prod.txt

and C:/BSKYB_CWE/many of log files in .txt format

Program Flow:

Step 1: The program will read the last sentence Hexa number from the file "Prod.txt"

Step 2: Once the program detecting the keyword like example "abcde" it will go to another folder which is descript in C:/BSKYB_CWE to look at which text files contains the keyword "abcde"

Step 3: this step will capture the whole line the text info like example 1111 abcde

if in this case, once the abcde detected what is the command i should apply to capture the key word 1111 ?

This is the problem i have encounter right now, i doesn't know how is actually can apply the right method to read the whole text line once the key word is detected

Public Class Form1
' Const ConstBSKYB = "C:BSKYB_CWE.txt "
'Const ConstBSKYBP = "C:BSKYBProd.txt"[code].....