/etc Across Unix Variants

Different Unix-like systems use different /etc files. In many commercial variants, these files are simply renamed or restructured files from primordial BSD.

For example, the first time I had to manage an IBM AIX system, I needed to know which disks should be mounted where, but there was no /etc/fstab. A little searching led me to /etc/filesystems, which was IBM’s /etc/fstab. Apparently, the IBM folks felt that a file named for “filesystem table” was confusing, so they gave it a different name. Knowing that this information existed somewhere in /etc, and knowing which files had an unrelated purpose, greatly shortened my search.

Changes to /etc can dramatically alter how your system performs. While manually recovering a scrambled filesystem can push an adequate sysadmin toward becoming a pretty good one, it’s one of the least pleasant ways to get there.