I have read the prefix has to be added after running
helm-m-x, but I don't know how to do it.
For example I want to pass an argument to
shell. When I run
helm-m-x and then C-u I see in the mode-line [prefarg:4]. On the next key press there will be 4 occurrences of the key instead of only the first one.
How can I do this?