Package/process ops · Lesson 12 of 20 · 8 minutes

Package file ownership

Map package names to owned files.

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Your objectives

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1
List package files
Run dpkg -L 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 -L fake-nginx
```
Remember: Repository availability and installed package state are separate evidence.
2
Read package owners
Run cat data/package-owners.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 data/package-owners.txt
```
Remember: Reading a source file should precede changing it; avoid printing real secrets.
3
Find nginx package files
Run grep fake-nginx data/package-owners.txt.
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 fake-nginx data/package-owners.txt
```
Remember: No matches is exit status 1, which is different from a malformed invocation.

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.
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

$ dpkg -L fake-nginx

/usr/sbin/fake-nginx
/etc/fake-nginx
/usr/share/doc/fake-nginx/README

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

$ cat data/package-owners.txt

fake-nginx:/usr/sbin/nginx
fake-nginx:/etc/nginx/nginx.conf
fake-openssh:/usr/sbin/sshd
coreutils:/bin/ls

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

$ grep fake-nginx data/package-owners.txt

fake-nginx:/usr/sbin/nginx
fake-nginx:/etc/nginx/nginx.conf

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 file ownership”, which interpretation is safe?A successful first check guarantees that every dependent service is healthy.Reading a source file should precede changing it; avoid printing real secrets.A command appearing in history proves it completed successfully.

Apply it elsewhere

Before adapting the cat workflow from “Package file ownership” 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: Package status log correlation Try an incident drill

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