What is stored in the /etc directory?
/etc is where system-wide configuration lives — almost all of it as plain, editable text files. It's the single place that defines how the machine behaves.
A defining Linux strength hides here: configuration is plain text, not a binary registry. That means you can read it, diff it, comment it, put it in version control, and copy a known-good config between machines — all with the same tools you use for any file. Editing /etc is a huge fraction of system administration.
| File | What it controls |
|---|---|
/etc/passwd |
User accounts (names, IDs, home dirs, shells) |
/etc/shadow |
Hashed passwords (readable only by root) |
/etc/group |
Group memberships |
/etc/hosts |
Manual hostname → IP mappings |
/etc/fstab |
Which filesystems mount where at boot |
/etc/ssh/sshd_config |
How the SSH server behaves |
Name origin: historically "et cetera" — the miscellaneous drawer — though it's now often backronymed as "Editable Text Configuration," which describes its modern role better.
Tip: Before editing any config, copy it first: cp /etc/sshd_config /etc/sshd_config.bak. A single typo in /etc/fstab or sshd_config can stop the system booting or lock you out over SSH — the backup is your undo button.