filtering a large file with a list of things

search.fsx

open System
open System.IO

// use an @ string
let list   = @"C:\list.txt"

// initialize a reader
let reader = new StreamReader(list)

// create a list of lines
let lines  = [ while not reader.EndOfStream do
               yield reader.ReadLine () ]

// filter to only the version we care about, by string match
let isolateVersion (s: string) (a: string) = a.Contains(s)
    
// filter and then print each line
lines
|> List.filter (isolateVersion @"MYKEYWORD")
|> List.map (fun line -> printfn "%s" line)