well, it does take work, but it can save time
let's say you have a file with 1000 lines
these lines have IP adressees, other numbers and messages
you want all messages saying "Login Failed" .. to see if someone is attacking your server (where you keep your data)
- you can then write a script to look for ALL those lines, and see if the same I has gotten that message many times (that would mean someone is repeatedly trying to log in without a valid password)... so you can find bad guys