I've looked through several tutorials and a couple of StackOverflow posts, but I've not seen any examples using sed or awk which use dates. I have a text file that contains this as the first line, I need to replace the date with the current date and time via script; what is the easiest way to do this in Linux? 

```

TS: 2014-03-31 13:56:01

```

I can use any tool available in a standard Ubuntu install such as sed or awk.