Terminal basics · Lesson 6 of 34 · 6 minutes

Command locations

Use which to understand how shells find commands.

Open the lab Course map

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Your objectives

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1
Locate nano
Run which nano.
Hint & worked example
Find the simulated executable path for a command.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
which nano
```
Remember: A path lookup does not prove that running the command will succeed.
2
Locate systemctl
Run which systemctl.
Hint & worked example
Find the simulated executable path for a command.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
which systemctl
```
Remember: A path lookup does not prove that running the command will succeed.
3
Locate ufw
Run which ufw.
Hint & worked example
Find the simulated executable path for a command.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
which ufw
```
Remember: A path lookup does not prove that running the command will succeed.

Understand the pattern

Knowing where commands come from helps debug confusing PATH issues.

which: Find the simulated executable path for a command.
A path lookup does not prove that running the command will succeed.

Worked example and expected result

$ which nano

/usr/bin/nano

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

$ which systemctl

/usr/bin/systemctl

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

$ which ufw

/usr/sbin/ufw

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 “Command locations”, which interpretation is safe?A successful first check guarantees that every dependent service is healthy.A path lookup does not prove that running the command will succeed.A command appearing in history proves it completed successfully.

Apply it elsewhere

Before adapting the which workflow from “Command locations” 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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