Security administration · Lesson 11 of 35 · 8 minutes

Script trust review

Hash and compare a training deployment script before trusting it.

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
Hash deploy script
Run sha256sum scripts/deploy.sh.
Hint & worked example
Compare content digests to detect byte changes, not to establish who authored the file.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
sha256sum scripts/deploy.sh
```
Remember: A checksum detects changes only relative to a trusted expected digest.
2
Read checksum file
Run cat data/checksums.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/checksums.txt
```
Remember: Reading a source file should precede changing it; avoid printing real secrets.
3
Inspect script
Run stat scripts/deploy.sh.
Hint & worked example
Inspect a file or directory metadata record, including ownership, permissions, and size.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
stat scripts/deploy.sh
```
Remember: Metadata and file contents answer different questions.

Understand the pattern

Supply-chain review starts with knowing what changed.

sha256sum: Compare content digests to detect byte changes, not to establish who authored the file.
A checksum detects changes only relative to a trusted expected digest.
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.
stat: Inspect a file or directory metadata record, including ownership, permissions, and size.
Metadata and file contents answer different questions.

Worked example and expected result

$ sha256sum scripts/deploy.sh

f7d569c8d8504a5ddbe9ac442362c65f068aeacd1f540b24ca1ec84b7c27359e  /home/learner/scripts/deploy.sh

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

$ cat data/checksums.txt

README.txt  fake hash changes when content changes
scripts/deploy.sh  review before running

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

$ stat scripts/deploy.sh

Path: /home/learner/scripts/deploy.sh
Type: file
Mode: -rw-r--r--
Owner: learner
Group: learners
Size: 85 bytes

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

Apply it elsewhere

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

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Log retention review Try an incident drill

Anonymous lesson and mastery progress lasts for this session. Sign in to keep synced lesson XP between sessions; mastery stays device-local. No speed bonus, lost lives, or hint penalties.

Keep learning

GNU Coreutils manual · GNU Bash manual