Originally in Unix, /usr
was used for user (home) directories. So if I had a user named alex
, my home directory would be /usr/alex
. (Interestingly, Plan 9, the successor to Unix, still has user directories in /usr
.)
Nowadays, of course, we store home directories in /home
. (At least on GNU/Linux. I don't know about other Unices, but OS X doesn't count.) At what point did this become standard practice? What Unix flavor did it appear in? How long did adoption by other Unices take? Has /home
been adopted by everyone?
I've done some searching on here, but turned up nothing.
Best Answer
This change was introduced by BSD after 1985 (BSD 4.2 was still documenting
/usr
) and in or before 1988 (BSD 4.3/SunOS 4.1hier(7)
manual page already documents/home
). It was quickly followed by Solaris 2.0 (which kind of merged System V and BSD) and was later adopted by most other Unix vendors.This is from the Solaris 2.0
useradd
manual page:Before that, older Unixes were using either the traditional
/usr
directory or some variants like /user1 documented in SVR3 and SVR4.0. Unix version 7hier(7)
manual page defines/usr
as the default location for user's home directory:Unix version 6, the first Unix to be widely released outside of the Bell Labs had not the
hier
manual page yet but was already using and documenting/usr
.There are several reasons that explain the move from
/usr
to something else, including:With some Unix versions, upgrading the OS was blowing away the
/usr
directory.Usernames like
tmp
,src
,bin
,local
and the likes were forbidden as they clashed with existing directories under/usr
.Using
/usr
as an automounter base directory was not possible as it was not empty (Thanks to Johan for pointing this)Diskless machines were expected to use a read only NFS share for
/usr
but read-write home directories