add command to switch between version

[proppy]

It'd be cool to have a new command to download and switch between version of the iso.

example:

$ b2d use 1.3.1
downloading 1.3.1 ...
using 1.3.1
$ b2d use 1.3.0
using 1.3.0
$ b2d version
iso: 1.3.0

[tianon]

I'd be down with this if someone wanted to do the legwork -- we just need
to make sure the current experience is preserved (ie, "boot2docker upgrade"
should automatically update to the latest and switch to it, etc). It would
also make it easier for "boot2docker upgrade" to determine that we've
already got the latest version downloaded, since the ISO would still be
around.

One issue I see is that we'll then need some way to help users "garbage
collect" old ISOs they don't care about anymore.

[SvenDowideit]

I would love the iso's to be stored on my disk using boot2docker-v0.5.iso versioned filenames. but on the other hand - whats the user-size for this?

[tianon]

Sorry, this repository is long-since deprecated in favor of Docker Toolbox (whose usage is now also discouraged in favor of Docker for Windows and Docker for Mac).