Server operations · Lesson 4 of 36 · 8 minutes

Resource inspection

Read simulated disk, memory, uptime, and directory usage signals.

Open the lab Course map

Mastery 0/3Run itExplain itApply it

learner@clairos:~ $

↑ history · Tab complete · Ctrl+C cancel · Esc, Tab to leaveExit 0

Your objectives

Hints are always available. Wrong turns never cost XP.

1
Check disk
Run df -h.
Hint & worked example
Inspect the virtual filesystem capacity report. Real systems can run out of space or inodes independently.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
df -h
```
Remember: Available space is a snapshot, not a guarantee that a later write will succeed.
2
Check log usage
Run du -sh /var/log.
Hint & worked example
Estimate usage attributed to files or directories; compare it with filesystem capacity when investigating storage.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
du -sh /var/log
```
Remember: du describes file usage, whereas df describes filesystem capacity.
3
Check memory and uptime
Run free -h and uptime.
Hint & worked example
Inspect simulated memory totals and availability. Read simulated runtime and load information.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
free -h
uptime
```
Remember: Allocated, cached, available, and free memory are not interchangeable measures. Load average is not a direct CPU percentage.

Understand the pattern

Capacity issues often explain service symptoms.

df: Inspect the virtual filesystem capacity report. Real systems can run out of space or inodes independently.
Available space is a snapshot, not a guarantee that a later write will succeed.
du: Estimate usage attributed to files or directories; compare it with filesystem capacity when investigating storage.
du describes file usage, whereas df describes filesystem capacity.
free: Inspect simulated memory totals and availability.
Allocated, cached, available, and free memory are not interchangeable measures.
uptime: Read simulated runtime and load information.
Load average is not a direct CPU percentage.

Worked example and expected result

$ df -h

Filesystem      Size  Used Avail Use% Mounted on
lab-root         20G  6.4G   14G  32% /
lab-logs        2.0G  180M  1.9G   9% /var/log

Exit status: 0. The command completed successfully in the training fixture.

$ du -sh /var/log

3K	/var/log

Exit status: 0. The command completed successfully in the training fixture.

$ free -h

               total        used        free      shared  buff/cache   available
Mem:           3.8Gi       820Mi       2.1Gi        18Mi       900Mi       2.8Gi
Swap:             0B          0B          0B

Exit status: 0. The command completed successfully in the training fixture.

$ uptime

 10:26:04 up 12 days,  4:18,  1 learner,  load average: 0.04, 0.03, 0.01

Exit status: 0. The command completed successfully in the training fixture.

Try a variation

Repeat this workflow in the sandbox with a different scratch filename. Keep the system fixtures unchanged and compare the observed output with your expectation before moving on.

Explain it

In “Resource inspection”, which interpretation is safe?du describes file usage, whereas df describes filesystem capacity.A command appearing in history proves it completed successfully.A successful first check guarantees that every dependent service is healthy.

Apply it elsewhere

Before adapting the du workflow from “Resource inspection” to another server, what should you do?Paste the training paths unchanged into production.Skip output inspection whenever the command is familiar.Confirm the current directory, target identity, permissions, and the installed command behavior first.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Host network view Try an incident drill

Anonymous lesson and mastery progress lasts for this session. Sign in to keep synced lesson XP between sessions; mastery stays device-local. No speed bonus, lost lives, or hint penalties.

Keep learning

GNU Coreutils manual · GNU Bash manual