2011-12-22

sauron: keeping an eye on what's going on

I'm a fairly busy person, and need to keep track of a lot of things. That includes following a bunch of internal IRC channels, attending meetings, meeting deadlines and so on. But I don't want to stare at my org-mode calendar, or flip through ERC buffers all the time.

Instead, I'd like to have one little emacs frame (window) that gathers these ('events'), and transfers me to wherever the event came from when I click it - some IRC-channel in ERC, my org-calendar etc. and other inputs. Note, using Bitlbee, you can include Facebook-contacts, GoogleTalk-buddies and Twitter-tweets, … in ERC - so, you can track just about anything.

In addition, with so many inputs, I'd also like the possibility to filter out unwanted events, and generate various light/sound effects and fireworks, proportional to the priority of the event.

For all this, I wrote a little emacs-tool called Sauron that does just that. M-x sauron-start pops up a frame that receives events, and M-x sauron-stop hides it and stops listening. It works with ERC, org, and listens for D-Bus messages; so it's pretty easy to get events from all over the place.

It's a bit of a balancing act to get all the important information while not being swamped in noise, but Sauron allows you to fine-tune it to whatever works the best for you. I've tried to have sane defaults though, so things should mostly work without too much configuration - but if you need the power, it's there. I also added some convenience functions to make it easy to get sounds and other special effects.

So - it's brand new, it is of seems-to-work-for-me-quality, and I'd like to invite others to try it out, hack it, give feedback, add new back-ends and so on – what better Christmas present to ask for!

There's documentation, examples etc. to be found in Sauron's github repository.

2011-12-10

system administration with emacs

When performing system administration tasks, one often needs to edit files owned by root.

For both security and safety reasons, it's a good idea to do as little as possible as root (or with root privileges). For that reason, you probably don't want to run Emacs as 'root', because it's simply too powerful. I often see people use vi (usually, vim) instead – but since it allows you to do just about anything as well (like running shell commands), that's not much of an improvement.

Now, a while back we discussed editing files owned by root with tramp – you can use emacs with your normal user-account, and use sudo to write the root-owned file. That makes it much harder to screw things up.

Another reason people use vi for little editing jobs is because its startup time is significantly shorter than the startup time for a new emacs instance. For that, however, we have emacs daemon.

Combining tramp and emacs daemon and a shell function:

# edit file with root privs
function E() {
         emacsclient -c -a emacs "/sudo:root@localhost:$1"
}               

Now, we can very quickly edit any file owned by root using 'E' --

$ E /etc/hosts

So, if you prefer emacs, there's little reason to use vi, even for editing system files – although I have to admit that it takes time to evict 'sudo vi <system file>' from my muscle memory.

Update reader Yi Wang mentions that, in fact, we can make this a bit more general using sudoedit; so, instead of using Tramp, we can use:

# edit file with root privs
alias E="SUDO_EDITOR=\"emacsclient -c -a emacs\" sudoedit"   

This works also without absolute paths.