Practice next
Read the concept, then use a quiz, builder or checklist to make it stick.
Quick reference
| Area | Commands or meaning |
|---|---|
| Website down | curl, DNS, server status, logs |
| DNS | NS, A, CNAME, MX, TXT, TTL |
| MX, SPF, DKIM, DMARC, bounce | |
| SSL | Hostname, expiry, chain, redirect |
| Disk | df, du, inodes, logs |
| Database | service, errors, size, processlist |
| WordPress | PHP errors, plugins, cache, cron |
How to use it
Do not memorise every flag. Memorise the situation, the first command to run, and how to check whether the output makes sense.
Practice prompt
Pick three entries from the table and create a tiny lab. For example, make test files, search them, change permissions, and explain what changed.