I've read and understand the FHS as well Bratag. I built my own linux off of it using that and the LFS documents. However, almost no mainstream distribution actually follows the guide 100%. Solaris and FreeBSD have different filesystem structures, Solaris using things /export, which is mostly non-existent in any other Unix-related operating system. It also isn't even in the "almighty" FHS. TLDP also has a "standard": http://tldp.org/LDP/intro-linux/html/sect_03_01.html.. which is similar - but not identical to the FHS. I think debian sums it up best: http://www.debian.org/doc/debian-policy/ch-opersys.html In short - with pretty much all linux: We follow this Standard..... except when we don't.