bug#22329: 24.3; Emacs Tramp feature suggestion: adding sg as a default connection method

[Peng Bai <baipeng@sina.com>]

Following up a question on Stack Overflow
(http://stackoverflow.com/questions/34643837/in-emacs-how-do-i-use-tramp-ssh-to-edit-as-a-different-group-id):

I suggest adding "sg" as a default connection method. My specific use
case is that I have an account on a server, and that user belongs to
multiple groups (main group "group_A", secondary group "group_B") for
administrative reasons. SELinux Access Control is used so even if a
directory is owned by me, but if my main group ID is not right, I will
not be able to create files. In an interactive session, I would do
"chgrp group_B" to switch my main group, and a new shell session will be
created. If remotely launching a program, I would do "ssh foo.com 'sg
group_B /path/to/executable'".

Currently I add the following to my initialization script:

(eval-after-load 'tramp
  '(add-to-list
    'tramp-methods
    '("sg"
      (tramp-login-program "sg")
      (tramp-login-args (("-") ("%u")))
      (tramp-remote-shell "/bin/sh")
      (tramp-remote-shell-args ("-c")))))

Thank you!

Best regards,

Peng