Station 2: Reading, Moving, and Removing

Reading Files

The first thing I wanted to do was look inside a file. I knew ls could show me filenames, but I wanted to see what was in them. The command for that is cat.

cat readme.txt

It printed the entire file to the screen. For a short file like readme.txt, that worked fine. Then I tried it on a larger file.

cat bundle.js

A wall of text blasted past faster than I could read. Hundreds of lines, gone in a blink. I was scrolling frantically when I heard a voice behind me.

I tried it.

less bundle.js

The file appeared one screen at a time. I could use the arrow keys to scroll up and down, spacebar to jump a full page, and q to quit when I was done. It felt like reading instead of drowning.

Two more commands worth knowing by name: head shows the first few lines of a file, and tail shows the last few. They both take flags to control how many lines. Copilot knows all the details whenever I need them.

Flags — Modifying Commands

I tried it on git.

git --help

A list of the most common subcommands and options git supports appeared. Commands I had never seen before. Options I did not know existed. The terminal was not hiding anything from me — I had not thought to ask.

"The terminal can explain itself." I said it out loud, to no one in particular. For deeper explanations of what specific flags do, Copilot can walk through them in context.

Copying and Moving Files

Copying a file is straightforward. The command is cp, and it takes two arguments: the source and the destination.

cp notes.txt notes-backup.txt

Now I had two files. The original was untouched. Over in VS Code, the sidebar updated in real time — notes-backup.txt appeared the moment I ran the command.

Moving a file uses mv.

mv notes-backup.txt archive/notes-backup.txt

The file disappeared from the current directory and appeared inside archive/. But then I discovered something that surprised me — mv is also how you rename.

mv old-name.txt new-name.txt

There is no separate rename command. Moving a file to a new name in the same directory is renaming. Once I understood that, it made sense — within the same disk, the filesystem does not distinguish between "move" and "rename." Both are just changing where a name points.

Why These Commands Matter

I was practicing — running cp, mv, cat, less — working through the commands Copilot had outlined in Station 1. Prof. Teeters walked by, noticed what I was doing, and paused for exactly one sentence.

"The terminal was here before agents, HAP. Today's best engineers still know the tools themselves."

She moved on. But I sat with that for a minute. I had been learning these commands to understand Copilot. But that was backwards. I should be learning them because I am a developer. The tools are mine, not my agent's.

Removing Files — The Dangerous One

The command is rm. I ran it on a test file I had created.

rm scratch-test.txt

Gone. No confirmation dialog. No trash can. No undo. I ran ls and the file was not there. The terminal believed me completely.

I got curious. I had read about flags, and I wanted to see what rm could do with them. I typed:

rm -rf

I had not pressed Enter yet. I was going to add a directory name. But before I could finish —

That was the only time in the entire lab that Grace left her terminal. I will not forget it.