Security administration · Lesson 13 of 35 · 7 minutes

Account hygiene

Review training accounts and root presence safely.

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

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1
Read passwd
Run cat /etc/passwd.
Hint & worked example
Read one or more files to standard output without editing their contents.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
cat /etc/passwd
```
Remember: Reading a source file should precede changing it; avoid printing real secrets.
2
Find root
Run grep root /etc/passwd.
Hint & worked example
Select input lines that match a pattern; -i ignores case, -n adds line numbers, and -v inverts selection.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
grep root /etc/passwd
```
Remember: No matches is exit status 1, which is different from a malformed invocation.
3
Show learner id
Run id.
Hint & worked example
Inspect user identity and group membership.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
id
```
Remember: A file group is useful only when the acting user belongs to it or has an applicable override.

Understand the pattern

Account review is a basic security administration skill.

cat: Read one or more files to standard output without editing their contents.
Reading a source file should precede changing it; avoid printing real secrets.
grep: Select input lines that match a pattern; -i ignores case, -n adds line numbers, and -v inverts selection.
No matches is exit status 1, which is different from a malformed invocation.
id: Inspect user identity and group membership.
A file group is useful only when the acting user belongs to it or has an applicable override.

Worked example and expected result

$ cat /etc/passwd

root:x:0:0:root:/root:/bin/bash
learner:x:1000:1000:Clairos Learner:/home/learner:/bin/fake-sh
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin

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

$ grep root /etc/passwd

root:x:0:0:root:/root:/bin/bash

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

$ id

uid=1000(learner) gid=1000(learners) groups=1000(learners),27(sudo-readonly)

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 “Account hygiene”, which interpretation is safe?No matches is exit status 1, which is different from a malformed invocation.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 grep workflow from “Account hygiene” 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: Final incident review Try an incident drill

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