"if sting in string"

[smadus via Digitalmars-d-learn]

Hello

Searching after hours, i give up and here is the question. ;)

I will make a programm, this searching all txt files on the 
system or the path from user and searching a user tiped term in 
this file.

http://dpaste.dzfl.pl/dec09a0f849c

The Problem is in the if() "line 17" i searching in 
std.algorithm, but i dont find a solution for my problem.

i hope, someone can help me.

I'm new on D and sorry for my bad english.

Happy Greetings

Shorty