FreeBSD offers write protection by allowing you to set files as immutable, to do this you will need to set set a special bit. Once this bit is set no one can delete or modify file, this includes the root user. The only user that can set and clear immutable bit is the root user.
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...Checking which Debian/Ubuntu version maps to each other can be a pain specially when you are following a tutorials on how to setup something of fix a bug. As not all users are going to know the differences between the versions I have posted a list which should help identify if you are looking at the...