I want to learn one more Linux distribution. I'm serious and "one more" means the second one. I've been using a Linux distribution for almost a decade, I like it very much, but I want to learn something new additionally.
I plan to go with a common /home partition to always have my preciousss config files at hand. While I plan to spend most of the time in the new distribution, I expect to be dual-booting sometimes. My main concern is to not screw file permissions in my home due to my users having different UIDs in the two distributions. I know that when creating an user (at least when doing it using CLI tools like useradd) I can explicitly specify the UID. What to do if the install of the new distro would allow me to create an user, but won't allow me to choose the UID explicitly? Just skip this step or create a stub user, then later create an user from command line? And what to do if the UID of my user in my primary distro would be already taken in the new distro? Any other ways to avoid these eventual troubles?
Are there any additional problems if my /home is encrypted? I do it using the LUKS-enabled cryptsetup.
I have done that once, and I do not recommend it. The reason is that distributions (mostly) do not use exactly the same version of applications. As an illustration, Ubuntu uses application X-APP version a.1 and Centos uses version a.2. When you boot Ubuntu and start X-APP for the first time, it creates ~/.x-app.rc. Later when you reboot into Centos and start X-APP it finds the ~/.x-app.rc which lacks some new features and tries to upgrade it to the appropriate style for a.2. It works good up to this point, but when once again you want to boot Ubuntu and use X-APP it would complain about a corrupted ~/.x-app.rc!
Sometimes it gets worse and there are conflicting applications or configuration in different distributions.
What I am doing at the moment is storing my documents, scripts and etc. in a shared partition but I do not share things like *~/.gnome** or ~/.kde across distributions.
You can alter the user uid with the command
usermodBut, as pointed before, I don't recomend you to use the same home dir for two different distros. From all the fancy rc files which lurk in the home dir users tend to tweak less than a dozen, the rest are normally managed by the software. And configuration files tend not to be backwards compatible.
You can symlink the ones you mantain and let the system manage others