[CentOS] sed a particular line in file

[Tom Brown]

> % cat foo
> Hello line 1
> Hello line 2
> Hello line 3
>
> # To change just line 2
> % sed '2s/Hello/There/'
> Hello line 1
> There line 2
> Hello line 3
>
> # To change line 2 and onwards
> % sed '2,$s/Hello/There/'
> Hello line 1
> There line 2
> There line 3
>
> It's that simple :-)
>
>   

yes indeed - simples