Efficient way to delete a line from a text file

Question

I need to delete a certain line from a text file. What is the most efficient way of doing this? File can be potentially large(over million records).

UPDATE: below is

Answer 1

Move you file to memory using File Mapping, like Think Before Coding did, and made deletions on memory and after write to disk.
Read this File Read Benchmarks - C#
C# accessing memory map file