Valve has been quite keen on pushing PC gaming to Linux platform, but it appears that Steam for Linux has a rather big bug that actually delete user files.
According to the report from
Neowin, the bug shows up when user try to moves the Steam directory and Steam actually runs a the command which starts deleting everything. This is a bad thing if the user is logged in as root or has write access to more than just the home directory.
Apparently, Valve is already working on a patch so things should be fixed soon, but for now, it is smart not to move your Steam directory in case you are gaming on Linux.
Source:
Neowin.net.