Text and logs · Lesson 37 of 38 · 8 minutes

Incident template numbering

Number a runbook template so collaborators can reference exact fields.

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Your objectives

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1
Number the incident template
Run nl data/incident-template.md.
Hint & worked example
Number input lines for a readable evidence reference.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
nl data/incident-template.md
```
Remember: Line numbers depend on the exact file version and numbering mode.
2
Find the evidence field
Run grep evidence data/incident-template.md.
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 evidence data/incident-template.md
```
Remember: No matches is exit status 1, which is different from a malformed invocation.
3
Count the template fields
Run wc -l data/incident-template.md.
Hint & worked example
Count input. -l counts newline characters, -w counts whitespace-delimited words, and -c counts bytes.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
wc -l data/incident-template.md
```
Remember: Text without a final newline may have fewer counted lines than visible rows.

Understand the pattern

Turning a text template into a reviewable checklist helps operators explain what they know before they change anything.

nl: Number input lines for a readable evidence reference.
Line numbers depend on the exact file version and numbering mode.
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.
wc: Count input. -l counts newline characters, -w counts whitespace-delimited words, and -c counts bytes.
Text without a final newline may have fewer counted lines than visible rows.

Worked example and expected result

$ nl data/incident-template.md

     1	summary:
     2	evidence:
     3	impact:
     4	next action:
     5	rollback:

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

$ grep evidence data/incident-template.md

evidence:

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

$ wc -l data/incident-template.md

4 data/incident-template.md

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 “Incident template numbering”, 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 “Incident template numbering” 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: Text evidence bridge Try an incident drill

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