Package/process ops · Lesson 13 of 20 · 8 minutes

Package status log correlation

Connect package status output to package logs.

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Your objectives

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1
Read nginx status
Run dpkg -s fake-nginx.
Hint & worked example
Inspect installed-package records in the synthetic Debian-style environment.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
dpkg -s fake-nginx
```
Remember: Repository availability and installed package state are separate evidence.
2
Find install log
Run grep install /var/log/dpkg.log.
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 install /var/log/dpkg.log
```
Remember: No matches is exit status 1, which is different from a malformed invocation.
3
Read nginx policy
Run apt policy fake-nginx.
Hint & worked example
Inspect a fixed training package inventory. The simulator cannot install or upgrade your computer.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
apt policy fake-nginx
```
Remember: Candidate, installed, and repository versions answer different questions.

Understand the pattern

Junior operators build confidence by gathering evidence before changing systems.

dpkg: Inspect installed-package records in the synthetic Debian-style environment.
Repository availability and installed package state are separate evidence.
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.
apt: Inspect a fixed training package inventory. The simulator cannot install or upgrade your computer.
Candidate, installed, and repository versions answer different questions.

Worked example and expected result

$ dpkg -s fake-nginx

Package: fake-nginx
Status: install ok installed
Version: 1.0-training

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

$ grep install /var/log/dpkg.log

2026-05-26 08:00:00 install fake-nginx 1.0
2026-05-26 08:02:00 status installed fake-nginx 1.0

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

$ apt policy fake-nginx

fake-nginx:
  Installed: 1.0-training
  Candidate: 1.0-training
  Version table: simulated

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 “Package status log correlation”, which interpretation is safe?A successful first check guarantees that every dependent service is healthy.No matches is exit status 1, which is different from a malformed invocation.A command appearing in history proves it completed successfully.

Apply it elsewhere

Before adapting the grep workflow from “Package status log correlation” 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.

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