exeln: EXEcute LiNe

The following exeln function passes the current line to the system shell, which executes it, thus EXEcuting LiNe.

On Windows x86, my GNU Emacs has shell-file-name set to cmdproxy.exe, which is provided by x86_64-w64-mingw32, with which Emacs was compiled.

shell is invoked synchronously by default; a prefix argument can change this to asynchronous.

In the video below, point is on a line of text that would print the contents of hello_whirled.txt when entered at the Windows command prompt (or DOS prompt). I press C-c x, which is bound to exeln. The command is executed and the output is shown in *Shell Command Output*, the default buffer used for synchronous output from shell-command.

(defun exeln (arg)
    "Execute the current line as a shell command.
With prefix arg, operate asynchronously, same as calling
(shell-command COMMAND) where COMMAND ends in '&'.
Otherwise, execute synchronously."
  (interactive "P")
  (let (asynch)
    (if arg
        (setq asynch "&"))
    (shell-command (concat
                    (buffer-substring
                     (line-beginning-position) (line-end-position))
                    asynch))))

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2026-06-04 Add demo video