My .emacs file calls server-start so I can use emacsclient from the shell to send random editing jobs to emacs. However, with multiple emacs processes running, I sometimes have to hunt around for the emacs instance that emacsclient sent the editing job to do. Bummer!

I'd prefer emacsclient to send all my editing jobs to a single, known emacs process (unless I tell it to use another). The server-name variable can help with this. The server-name value, which defaults to "server", affects the name of the unix domain socket that emacs opens for emacsclient's use. The default socket file is "/tmp/emacs<user-uid>/server". The command "emacsclient -s " uses the socket named <server-name> to send the editing job to the emacs process owning the socket. So it would seem that the following settings in your .emacs would do the trick:

(setq server-name "my-server") 
(start-server)

However, if you start another emacs process, it will clobber the existing socket file and subsequent emacsclient requests to "my-server" will go to the new process. Furthermore, emacs doesn't clean up the socket files on exit. This makes it tough to detect if a server with a particular server-name is running.

Below is a wrapper around server-start that helps. First, it allows you to easily name the server. Secondly, it arranges for emacs to delete the socket files it owns when emacs shuts down. This allows the function to use the existence of the socket file to decide if a server process exists for a given name -- so there is a way to refuse to start the server if an existing emacs process is already running it.

(require 'server)

(defun start-named-server (name)
  "Start a server named 'name' - ensure only 1 server of that name is running"
  (interactive "sServer Name: ")
  (setq server-name name)
  (setq mk-server-socket-file (concat server-socket-dir "/" name))
  (unless (file-exists-p mk-server-socket-file)
    (server-start)
    (add-hook 'kill-emacs-hook
              (lambda ()
                (when (file-exists-p mk-server-socket-file)
                  (delete-file mk-server-socket-file))))))

(start-named-server "server") ; default server-name

Additional emacs instances can start a server via "M-x start-named-server ENTER <server-name>".

Technorati tags for this post: emacs

I've posted a new project handling library to the Emacs Wiki: mk-project.el. A "project" in this sense is a directory of source files. You define a named project and provide settings for it: base directory, source file patterns, file patterns to ignore, the TAGS file, the compile command, etc.

Features:

• Quickly switch between projects, optionally closing the files in the old project.
• Use the new project's TAGS file -- and be able to rebuild the TAGS file based on project settings.
• Run find-grep from the new project's base directory, ignoring certain files or directories based on project settings.
• Run compile with the project's preferred compile command.
• Open any file in the project quickly based on regex matches.
• Quickly open dired on the project's base directory.
• Define per-project startup and shutdown hooks -- useful for opening often-used files.

Perhaps the feature I'm happiest with is project-find-file. The library maintains a list of all the files under the project's base directory in a special buffer, *file-list*. Project-find-file ask for a regular expression representing part of a file's path or name and either 1) opens the file if there is only one match in *file-list*, or 2) allows selecting among the matching files with Emacs' built-in completion mechanism. Also, it sometimes comes in handy to search buffer *file-list* directly when you want an overview of the entire project. I often work with projects having thousands of files in deep folder hierarchies so project-find-file is very convenient.

After writing my library, I discovered a similar library, ProjMan by David Shilvock. The project operations we offer are similar - we even recommend similar keybindings! ProjMan is perhaps more complete, but I don't feel my time was wasted writing mk-project.el -- elisp is pleasure to code in.

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