For what it's worth, the /proc filesystem is not on all UNIX /UNIX-like OSes. I believe it originated in Linux, and FreeBSD has a procfs interface as well, alth

For what it's worth, the /proc filesystem is not on all UNIX /UNIX-like OSes. I believe it originated in Linux, and FreeBSD has a procfs interface as well, although it does not have all the bells and whistles you will find in Linux. OpenBSD on the other hand, does not have procfs at all.