[Help-bash] eval

[Wu Shuangrong]

let say:
$> a=‘one two     three”
$> eval ‘b=$a’
$> printf “%s\n” “$b”

you will get “one two    three”.

What’s confusing me is that why this is working this way. From my point of 
view, after expansing, 'b=$a’ will become ‘b=one two   three”, so the command 
to be 
evaluated is ‘b=one two    three’, but there is not a command called two, so it 
will fail. But it does not. So what’s happening here?