GNU screen understands special escape sequences to invoke screen commands.  You can use this to launch new screens from eshell.  For this to work, you must grant permissions for the :window: screen user to run things, using the following screen command (place in your ~/.screenrc):

  acladd :window:


As an example of this, here's a little trick to get "ssh" in eshell to launch ssh in a new screen when running under GNU screen, or a new xterm when running under X.  Otherwise, ssh is run in a new term buffer.

 (defun eshell/ssh (&rest args)
  "Secure shell"
  (let ((cmd (eshell-flatten-and-stringify
              (cons "ssh" args)))
        (display-type (framep (selected-frame))))
    (cond
     ((and
       (eq display-type 't)
       (getenv "STY"))
      (send-string-to-terminal (format "\033]83;screen %s\007" cmd)))
     ((eq display-type 'x)
      (eshell-do-eval
       (eshell-parse-command
	(format "rxvt -e %s &" cmd)))
      nil)
     (t
      (apply 'eshell-exec-visual (cons "ssh" args))))))

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CategoryEshell