Question: I am creating a rake task that would re-upload a file in S3 when it gets changed between HEAD and HEAD^1. Which git command should I use to do this. Does it make sense to compare the `hash-object` of those two?

Answer: 
You can do it with substring.

```
string strNumber = "1111222233334444";

string []strArr = new string[4];

for(int i=0; i < 4; i++)
{
   strArr[i] = strNumber.Substring(i*4, 4);
}

```
You can use Regex to do it in a single line:

```
var res = Regex.Split(str, "(?<=\\G\\d{4})");

```

**NOTE:** This works fine under Microsoft .NET, but does not work with Mono's implementation of Regex.