Note that in general this is not a one-to-one replacement. `%!cmd` sends the current buffer contents to `cmd`’s stdin and replaces the buffer with `cmd`’s outpu

Note that in general this is not a one-to-one replacement. `%!cmd` sends the current buffer contents to `cmd`’s stdin and replaces the buffer with `cmd`’s output. In the case of ‘ls’ this works since it doesn’t take anything on stdin