Terminal basics · Lesson 3 of 34 · 7 minutes

Hidden files

Use long and all listings to reveal dotfiles and read shell startup notes.

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
Show hidden files
Run ls -la /home/learner.
Hint & worked example
List directory entries; -a includes hidden names and -l adds ownership and permission detail.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
ls -la /home/learner
```
Remember: A listing is not proof that you can read or modify every listed file.
2
Read the profile
Run cat ~/.profile.
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 ~/.profile
```
Remember: Reading a source file should precede changing it; avoid printing real secrets.
3
Inspect SSH folder
Run stat ~/.ssh.
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 ~/.ssh
```
Remember: Metadata and file contents answer different questions.

Understand the pattern

Admin work often depends on hidden configuration files.

ls: List directory entries; -a includes hidden names and -l adds ownership and permission detail.
A listing is not proof that you can read or modify every listed file.
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

$ ls -la /home/learner

--rw-r--r-- learner learners   105 .profile
ddrwx------ learner learners   dir .ssh
ddrwxr-xr-x learner learners   dir archive
ddrwxr-x--- learner learners   dir backups
ddrwxr-xr-x learner learners   dir data
ddrwxr-xr-x learner learners   dir lab
ddrwxr-xr-x learner learners   dir notes
ddrwxr-xr-x learner learners   dir projects
--rw-r--r-- learner learners   148 README.txt
ddrwxr-x--- learner learners   dir restore
ddrwxr-xr-x learner learners   dir scripts

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

$ cat ~/.profile

export PATH=/home/learner/bin:/usr/local/bin:/usr/bin
alias ll='ls -la'
# fake shell profile for training

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

$ stat ~/.ssh

Path: /home/learner/.ssh
Type: dir
Mode: drwx------
Owner: learner
Group: learners
Size: 3 items

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 “Hidden files”, 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 “Hidden files” 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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