Multibit - error (or at least confusion) in 'How to check digital signatures" info for noobs
I also am having trouble getting the hashes to match on a Windows system (MultiBit, Bitcoin-Qt .zip and .exe).  I am using Microsoft's "unsupported" tool that the "hash document" references.  I suspect that I will have better results using Linux.

In response to your specific issue, the "$"  at the beginning of the command is the actual prompt.  This implies the command is being entered in a linux\UNIX "shell" (i.e. bash shell).  If it were a windows system you would see something like "C:\User\Sam> echo "Hello world" > example.txt"  The command still works in windows, but as you pointed out the output file is different.  In Linux/UNIX the same command would yield a file with only: Hello world     No punctuation, extra spaces or lines.  Therefore, the hash would be different under linux vs windows following the same command-line input.