Editing CU Research Computing (section)

== ESS on your local Emacs ==
Running Emacs (or Aquamacs) on your local computer, but editing files and using R on RC is not difficult, but requires some setup.
=== Setup ===
First, edit your local .emacs file and add the following statement
<syntaxhighlight lang="lisp">
(setq tramp-ssh-controlmaster-options
                 (concat
                   "-o ControlPath=~/.ssh/%%r@%%h:%%p "
                   "-o ControlMaster=auto -o ControlPersist=no"))
</syntaxhighlight>
This will cause tramp to share the same SSH socket as your login.rc.colorado.edu SSH sessions. That way you can open files without having to re-enter your OTP.

=== Opening a remote file with tramp ===
Opening a file on a remote host with tramp is similar to opening a local file. Press <tt>ctrl-x ctrl-f</tt> and then for the remote file enter <tt>/ssh:login.rc.colorado.edu:</tt> and then enter the path to the file, for example <tt>/ssh:login.rc.colorado.edu:/work/KellerLab/myfile.R</tt> or <tt>/ssh:login.rc.colorado.edu:scripts/mystuff.R</tt>. Once a single path element (<tt>/work</tt> or <tt>~/</tt>, for example> is entered then tab completion will work.

=== Activating a remote R session in ESS ===
Activating a remote R session is accomplished by using a shell within Emacs. It is most convenient to open a new Emacs frame with <tt>ctrl-x 5 2</tt>. Then within the new frame enter <tt>M-x shell</tt>. Then from the shell within Emacs run <tt>ssh login.rc.colorado.edu</tt> and then from that shell run <tt>ssh himem04</tt> or <tt>ssh node0219</tt> or whatever to get to the location where you actually want to run R.

Once you have a shell on your job node, then run R by typing <tt>R</tt>. Then run <tt>M-x ess-remote</tt> and then press enter to accept the Dialect line that is put up.

Once that is done you will be able to edit an R script in your local Emacs and submit lines to the R process on the RC job node.