Updated readme file to include --reinstall-packages-from

[reybango]

I wanted to add the syntax and example usage for the --reinstall-packages-from when migrating packages to a new Node install to the Readme file.

[ljharb]

Thanks! Could you also add nvm install node --reinstall-packages-from=node, and perhaps change this line to nvm install v0.12.7 --reinstall-packages-from=0.12 to convey that the "from" version is read before installing the new one?

[reybango]

Happy to make those changes. Could you give me just a little more info on what this does:
nvm install node --reinstall-packages-from=node

And on this nvm install v0.12.7 --reinstall-packages-from=0.12, do you mean to convey that the "from" is read before installing to verify that it exists or for some other reason? Asking so I can word it appropriately.

[ljharb]

Sure - basically, it first says nvm version node and resolves that to v0.12.6 in your example, then installs whatever node resolves to on the remote (v0.12.7 in your example), and then runs nvm reinstall-packages v0.12.6.

[reybango]

So to be clear, how would it know to resolve to v0.12.6 by using this syntax?
nvm install node --reinstall-packages-from=node

[ljharb]

Assuming 0.12.6 was the latest node version installed, node is an alias for stable which is an alias for "last even minor version of node" which resolves to 0.12.6

[reybango]

How does this look:

If you want to install a new version of Node.js and migrate npm packages from a previous version:

nvm install node --reinstall-packages-from=node

This will first use "nvm version node" to identify the current version you're migrating packages from. Then it resolves the new version to install from the remote server and installs it. Lastly, it runs "nvm reinstall-packages" to reinstall the npm packages from your prior version of Node to the new one.

You can also install and migrate npm packages from specific versions of Node like this:

nvm install v0.10.40 --reinstall-packages-from=0.10.39
nvm install v0.12.7 --reinstall-packages-from=0.12.6

[ljharb]

This looks awesome. Probably should also add nvm install iojs --reinstall-packages-from=iojs right below the node example, so that's covered too, but otherwise LGTM!

Thanks again!