Permissions and users · Lesson 7 of 33 · 7 minutes

Passwd and group files

Read training account and group records.

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
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
Read group
Run cat /etc/group.
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/group
```
Remember: Reading a source file should precede changing it; avoid printing real secrets.
3
Find learner group
Run grep learner /etc/group.
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 learner /etc/group
```
Remember: No matches is exit status 1, which is different from a malformed invocation.

Understand the pattern

Account review often begins with these files.

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.

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.

$ cat /etc/group

root:x:0:
learners:x:1000:learner
www-data:x:33:
adm:x:4:learner

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

$ grep learner /etc/group

learners:x:1000:learner
adm:x:4:learner

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 “Passwd and group files”, which interpretation is safe?Reading a source file should precede changing it; avoid printing real secrets.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 cat workflow from “Passwd and group files” 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.

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