A quick and dirty F# Shell Script to filter a text file for all lines which match a certain string

FilterTextFile.fsx

(*
* Filter a specified file into a second file
* Onorio Catenacci
* 21 October 2011
*)
#r "System.dll"

open System.IO

//Remember:
//When running from the command line, the first argument that isn't the script name is 1
//When running from FSI window, the first argument that isn't the script name is 0
let main (args:string[]) =
   let source_file = args.[1]
   let target_file = args.[2]
   let t_strings = File.ReadAllLines(source_file) |> Array.filter (fun cl -> cl.StartsWith "Unit Disposition")
   File.WriteAllLines(target_file,t_strings)
   0

main fsi.CommandLineArgs;;