directory naming explanation

Question

Where can I find an explanation of directory names used in Ubuntu (the whole tree)?

• Why etc?
• When do I put my files in /usr/local when in /home/usr when in /usr/local/bin and when in /var/lib/ or /bin?

Is there any rule, that tells when I have program x, it for sure must be placed here, and it's config files are here and data there.

Answer 1

The questions you're asking are answered in the hier(7) man page. See http://manpages.ubuntu.com/manpages/lucid/en/man7/hier.7.html for an online version.

Answer 2

look at File System Hierarchy Standard

also LSB spec can be helpful.