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8 December, 2016

Service disruption to ash

ash.waxworlds.org will be down for maintenance for approximately 1 hour tomorrow evening at 9pm GMT, after which time it will have more RAM.

Update: all done. [2016-12-09]


6 December, 2016

Service disruption to oak

oak.waxworlds.org will be down for approximately 2 hours tomorrow evening at 6pm GMT while work is undertaken on the power.

Update: work has been completed on schedule. [2016-12-07]


25 November, 2016

Spaces within parenthesis in emacs

There’s lots of opinion about coding styles and which is best. I prefer one that helps you read the code. And, to that end, I prefer to have spaces inside parenthesis, like this:

for( int a = 0; a < 20; a++ ) {
    dump( data[ a ] );

Call me a heathen if you like, but it’s how I roll!

And it’s how I set out to configure emails to help me roll…

Unfortunately, emacs’s electric-pair-mode doesn’t do this sort of thing and can’t be configured to, either. There are two problems. The first is that electric-pair-mode doesn’t allow for conditions as to when it will insert a pair. So, I could add a pair of spaces, (?\s . ?\s), to electric-pair-pairs so that it would automatically insert a second space, but it would do this for every space I typed. The second problem is that electric-pair-mode does some white-space skipping internally, which I think would be problematic. :(

So I did it the old-fashioned way and added my own functions:

(defun my/c-mode-insert-space (arg)
  (interactive "*P")
  (let ((prev (char-before))
        (next (char-after)))
    (self-insert-command (prefix-numeric-value arg))
    (if (and prev next
             (string-match-p "[[({]" (string prev))
             (string-match-p "[])}]" (string next)))
        (save-excursion (self-insert-command 1)))))

(defun my/c-mode-delete-space (arg &optional killp)
  (interactive "*p\nP")
  (let ((prev (char-before))
        (next (char-after))
        (pprev (char-before (- (point) 1))))
    (if (and prev next pprev
             (char-equal prev ?\s) (char-equal next ?\s)
             (string-match "[[({]" (string pprev)))
        (delete-char 1))
    (backward-delete-char-untabify arg killp)))

They can be bound in c-mode and c-mode derivatives like this:

(add-hook 'c-mode-common-hook
          (lambda ()
            (local-set-key " " 'my/c-mode-insert-space)
            (local-set-key "\177" 'my/c-mode-delete-space)))


6 October, 2016

Service disruption to oak

It would appear that our service provider have made a misconfiguration whilst transferring IP addresses to the new DSL (see post for 2016-10-02). As a result, oak is currently down.

Mail and jabber will most notably be affected, although no mail should get lost (it will come through when oak comes back on-line).

Apologies for any inconvenience. I will update as I resolve the issue with our provider.

Update: The issue has now been resolved. All services should be up and running as normal again and mail will no doubt start trickling through again. [2016-10-06]


2 October, 2016

Temporary IP address changes to oak

As of Sunday 2nd October, the IP address of oak.waxworlds.org may change temporarily. DNS records will be updated accordingly, and there should be minimal service disruption. Oak's IP address should revert to that previously assigned in a few days. I'll update this post as I hear more.

Update: The IP address has changed. DNS has been updated. The interface of oak's default route has also changed, so please report any problems. [2016-10-02]

Update: Our service provider appears to have made a misconfiguration whilst transferring IP addresses. As a result, oak is currently down. [2016-10-06]

Update: IP addresses have been restored, although oak's IP address has actually changed to a different one within the subnet. Hopefully everything should be working again now. [2016-10-06]


19 November, 2015

Server software update and migration

I will be updating ash to Debian 8 on Sunday 22nd November. There should be vitually no disruption, aside from a reboot.

I will also be moving oak to a new machine (which will be running Debian 8). There may be a brief disruption to mail and xmpp while I transfer configuration, etc.

I'll update this post with further info.

Update: This entire upgrade/migration has been postponsed due to a) an issue with oak's new hardware, and b) a hardware issue that is preventing backups on willow.


8 October, 2015

Using a shell in Emacs

Emacs Pumpkin

Emacs rocks.

It’s true, it does.

Recently, though, I’ve been trying to streamline my use of the shell in Emacs. Here’s my Halloween Emacs tips.

Added support for multiple shells

The first, glaring problem with shells in Emacs is that you can only have one.

I added a function that creates a shell based on the remote host of a buffer. It also names the shell after that host, so if I’m working on /example.com:/some/file, I’ll get a shell called *shell:example.com* (instead of just *shell*). This allows you to have multiple shells open simultaneously, one per host. [Credit: EmacsWiki]

(defun my/shell (&optional buffer)
   (let* ((tramp-path (when (tramp-tramp-file-p default-directory)
                        (tramp-dissect-file-name default-directory)))
          (host (tramp-file-name-real-host tramp-path))
          (user (if (tramp-file-name-user tramp-path)
                  (format "%s@" (tramp-file-name-user tramp-path)) ""))
          (new-buffer-name (format "*shell:%s%s*" user host)))
     (shell (if host new-buffer-name buffer))))

Added F9 shell toggle

Then I added the F9 global key binding to toggle between the current buffer and the related shell for the current buffer’s host, creating that shell as necessary.

(defun my/shell-toggle (&optional buffer)
  (if (string-match "^\\*shell[\\*:]" (buffer-name) )
      (my/shell buffer)))
(global-set-key [f9] 'my/shell-toggle)

Handle shell termination

There are several ways you could handle terminating the shell. You could, just for shell buffers, turn off the prompt that asks you if you’re sure you want to kill a buffer with an active subprocess running in it, and then use C-x k. But this would kill bash rudely, and bash would not save your command history. You could tell bash to save command history after every command. But this leaves executed commands between different shells all intermixed in the history file and shells would no longer have their own individual session history. That doesn’t appeal to me.

So I opted for another method: detect when the shell terminates and close the emacs buffer. This way, you can hit Ctrl-D (same as you would in a terminal window), bash saves its history, and everyone’s happy.

(add-hook 'comint-exec-hook
          (lambda ()
            (set-process-sentinel (get-buffer-process (current-buffer))
(defun my/shell-process-sentinel (process state)
  ;; show shell status and kill the buffer automatically
  (message "shell: %s" state)
  (if (or
       (string-match "exited abnormally with code.*" state)
       (string-match "finished" state))
      (kill-buffer (current-buffer))))



20 March, 2015

New cloud facilities

We are now running ownCloud at cloud.waxworlds.org. If want a user account created, please get in touch.

(FYI: ownCloud allows you to upload and sync files and documents between devices and then share them publicly or privately between other owncloud users or anyone who you gave a link to.)


16 March, 2015

Oak moving location

Oak is due to move home on 18th March and it's IP address will change again. There may be a 24hr delay as DNS catches up. As usual, please report any problems.

Update: Oak has moved. There may be a 24hr delay with DNS as caches expire. [2015-03-19]


27 February, 2015

Mail server listed in spam RBL

Due to mail.waxworlds.org (a.k.a. oak.waxworlds.org) being temporarily assigned a dynamic IP address, it has been listed in the SORBS DUHL spam RBL.

This is being persued with SORBS. I will post updates as they become available.

Update: SORBS will not unblacklsit oak while it has a dynamic IP address. It will move to a static address on 17th March. Appologies for any inconvenience in the meantime. [2015-03-09]

Update: This issue should be resolved after the forthcoming move. Appologies for any inconveniences. [2015-03-16]