Just in case any Apple users out there haven’t already installed the new OS X, Yosemite, beware of an anomaly in the installation process. Apparently, the installation moves /usr/local out of the way during installation and when everything is installed, it moves the contents back file by file.
This happens right at the end. Everyone I’ve talked to says it happens when the installation says it has 2 minutes remaining. If you’re installing on a new machine the whole thing goes pretty quickly. On a machine that’s already seen some use it can take longer. I imagine that would be particularly true for development machines.
In my case, I started the installation of my iMac, aineko, in the early morning and it hadn’t completed when I went to bed. I almost restarted everything but DuckDuckGo advised me to wait. Happily, I did that and in the morning it was ready to go. I don’t know how long it took but it was easily over 12 hours.
So the takeaway is that you should just wait if the Yosemite installation appears to hang.