The quiet risk on a phone is not a dramatic attack. It is a secret typed on the command line, a file left in shared storage, or a permission you granted months ago and forgot. This set covers the trail your own work leaves.
Each one is marked as you go, and the explanation arrives straight after, which is
the part worth reading.
4 questions, marked as you go.
Tasks
These need your own device. Run the command in Termux, then paste what it printed.
The marking looks at what the output means, so spacing, version numbers and
ordering do not matter. If you have not installed anything yet, the
lesson covers the setup.
See what a history file keeps
This writes three lines into a file in your home directory, in the shape a shell history file takes, then counts them and prints them. Look at the middle line and think about where it came from.
Run this in Termux
On your own device. Nothing on this page executes it. The command runs in
your terminal, and this box only reads what you paste back.
Nothing here is encrypted or hidden. It is a plain text file, and cat reads it.
three lines were counted
the whole command line is stored in plain text
the count and all three lines are there
the commands actually ran
What a good answer looks like
Four lines: the count, which is 3, then the three commands. The middle one is stored in full, including the account it was aimed at, in a file that anything running as you can read. That is what the lesson means by treating anything typed into a terminal as recorded. A secret belongs in a prompt or in a file with tight permissions, never on a command line.
Marking your own work
Both halves of this are checked in your browser, with no server involved, so nothing
stops you from pasting output you did not run. The tasks are written so that the
easiest way to pass one is to actually do it and read the result, which is the whole
intention.