I don't understand the underscore motion in vim, at least in the context of yank (y). My cheat sheet reads
"soft" bol down
which I do not comprehend. If I use the motion alone it seems to be the same as
^ which means go to the first non-whitespace in the line. However, if I use the motion with
y then it yanks the whole line (like yy or Y), but
y^ does not yank the whole line, but just to the first non-whitespace character, exclusive, as you might expect.
So, what exactly is underscore supposed to do?