How can I replace each new line with a auto-incremented number?

I am lookind for a effective way that I can replace newlines with an auto-incrementing number.

eg.

this is line 1
this is line 2
this is line 3
this is line 4

to

1. this is line 1
2. this is line 2
3. this is line 3
4. this is line 4

Is looping through each line the only way? I guess thats the way I will implement it for now. Unless I find a better way here :) Just some pseudo code will do. But I am using C#开发者_运维技巧

This is probably easier if you use a shell command, for example:

nl -ba -s'. ' -w1

Just some pseudo code will do.

int lineNo=1;
for(String str:listOfString){
System.out.println(lineNo + " : " +  str);
lineNo++;
}  

Note: code provided is written in java , You can get the basic idea from that

You can use LINQ:

string[] lines = ...

string newText = string.Concat(lines.Select(
                     (line, index) => string.Format("{0}. {1}", index, line)));