Terminal basics · Lesson 13 of 34 · 7 minutes

Output redirection

Write simple command output into a safe lab file.

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
Print status
Run echo status ok.
Hint & worked example
Write simple text to standard output. Prefer printf when exact formatting matters.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
echo status ok
```
Remember: Redirection can overwrite an existing file before the command runs.
2
Write status
Run echo status ok > lab-status.txt.
Hint & worked example
Write simple text to standard output. Prefer printf when exact formatting matters.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
echo status ok > lab-status.txt
```
Remember: Redirection can overwrite an existing file before the command runs.
3
Read status
Run cat lab-status.txt.
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 lab-status.txt
```
Remember: Reading a source file should precede changing it; avoid printing real secrets.

Understand the pattern

Redirection is useful, but it can overwrite files in real shells.

echo: Write simple text to standard output. Prefer printf when exact formatting matters.
Redirection can overwrite an existing file before the command runs.
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.

Worked example and expected result

$ echo status ok

status ok

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

$ echo status ok > lab-status.txt

(no output; exit 0)

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

$ cat lab-status.txt

status ok

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 “Output redirection”, which interpretation is safe?A successful first check guarantees that every dependent service is healthy.Redirection can overwrite an existing file before the command runs.A command appearing in history proves it completed successfully.

Apply it elsewhere

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

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Reset the lab Try an incident drill

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