Emacs equivalent of this Vim command to run my tests?

Question

I'm using Emacs at the moment and experimenting with it for my Rails development and there is one thing that I do quite regularly in Vim and I'd like to know if an equivalent exists in Emacs, or an alternative workflow to achieve the behavior that I need.

The command in Vim is

:map ;t :!rspec --no-color %<cr>

Essentially this maps a key combination to run a bash/shell command on the file represented by the current buffer (% expands to the filename at runtime, the <cr> is just a carriage return at the end to execute the command).

I map all sorts of random little commands as and when I need them and I really miss the immediacy of this approach.

How can I achieve something similar?

Answer 1

this function prompts for a command and runs that on to the current buffer file. if no file is associated to current buffer gives an error

(defun shell-command-on-buffer-file ()
 "prompts for a command and executes that command on to the associated 
 file of current buffer. if no buffer is associated gives an error"
  (interactive)
  (or (buffer-file-name) (error "no file is associated file to this buffer"))
  (let* ((my-cmd (read-shell-command "Command to run: "))
         (cmd-to-run (concat my-cmd " " (buffer-file-name))))
   (shell-command cmd-to-run)))

as usual emacs saves history of commands you have given so far, those can be accessed using M-p,M-n