from Crosh. This command, like the "shell" command, however, only works in developer mode, so the steps to switch to that and back again still apply, and will still apply even as M53 makes its way down the channels.
Update 2/17/2015: Users have been reporting error messages trying to use the command below. However, the good Craig Tumblison came to the rescue: The parameters have changed. Updating the post to reflect those changes.
People with Chromebooks have seriously wondered why a canary build of Chrome OS seems to not exist. They only see Stable, Beta, and Dev options in the "chrome://chrome" channel switcher... with nothing beyond that. They've seen posts in bug reports mentioning Canary builds, but no one has taken the time to mention how these people got the builds, as most of them are indeed Googlers. However, they do exist, and after personal snooping, I did indeed find out that they're easier to install than once thought.
If you do indeed have the guts to attempt this, be warned: the installation process, followed by the hellishly unstable user experience you'll end up with when finished, is certainly not for the faint of heart, and
Thanks for the tip, Joe.
Enter Developer Mode
Run the update
update_engine_client --channel=canary-channel --update
The first parameter ― "-channel=canary-channel" ― sets the channel to canary via the command line. The second ― "-update" ― will run a "ForcedUpdate" app version command, which will, as you'd expect, force an update without checking. It of course will take a while, so be patient. It's also not for the faint of heart, because the progress is shown as a long decimal between 0 and 1 instead of a percentage.
Revert back to verified mode
Assuming you know what you're doing, here's what you'll end up with when updating (as of December 27, 2013), in terms of system information (this is of course on an Acer C720, one of those devices without a physical dev switch):
Note the lack of a yellow Chrome Canary logo. That's because, in Chrome OS, two versions of Chrome can't coexist like they can on other platforms. So, you get the same old multi-colored logo in Chrome OS Canary that you'll find in Chrome OS otherwise. However, notice how there's also no channel-switcher? Again, Chrome OS Canary is a whole different animal compared to other versions. Canary builds are not allowed to be easily interchangeable with other versions, and as such, you won't find a channel pull-down at all when you update. As of this writing, the current Canary build of the Chrome browser that makes up the brunt of the OS is 34.0.1756.0 — again, one major major version ahead of the Dev Channel, which is stuck on 33 — and consequently, one major major version more unstable. Expect to see more bugs, more crashes, and, oh yeah, more visits to crbug.com/new than usual. Remember that the next time you try something like this.