# The compress engine — for idiots
> **Class:** `idiot`. Every step, nothing assumed. Goal: **compress a folder into a `.znippy`
> archive and list it**, from a cold shell to a finished file. If you already know Rust and the
> CLI, read [`compress-guide.md`](compress-guide.md) instead — this one spells out every keystroke.
## What you need first
- A terminal (the black window where you type commands).
- The znippy repo on disk.
In the terminal, type this and press **Enter** to go into the repo:
```
cd /run/media/rickard/T9/git/znippy
```
## Step 1 — build the tool
Type this and press **Enter**. It compiles the znippy command-line program. The first build
takes a while; that is normal.
```
cargo xtask build --suite ORIGINAL --atom znippy
```
When it finishes, the program lives at `./target/release/znippy`. The `--release` part means
"build the fast version" (without it you get a slower debug build).
## Step 2 — make a folder to compress
You need something to pack. Make a small test folder with two files in it — type each line and
press **Enter** after each:
```
mkdir testdir
echo "hello one" > testdir/a.txt
echo "hello two" > testdir/b.txt
```
Now `testdir` is a folder with two text files. That is what we will compress.
## Step 3 — compress the folder
Type this and press **Enter**:
```
./target/release/znippy compress -i testdir -o test.znippy
```
What each part means:
- `compress` — the thing we want znippy to do.
- `-i testdir` — the **input**: the folder to pack.
- `-o test.znippy` — the **output**: the archive file to create.
When it finishes you will have a new file called `test.znippy` in the current folder. That single
file holds both of your text files, compressed and indexed.
## Step 4 — look inside the archive
Type this and press **Enter**:
```
./target/release/znippy list test.znippy
```
This prints every file stored in the archive. You should see `a.txt` and `b.txt`. If you do, it
worked — the archive is real and readable.
## Optional flags (only if you need them)
You do **not** need these for the steps above, but here is what they do if you see them:
- `--no-skip` — compress **everything**. Normally znippy skips already-compressed files (like
`.png` or `.gz`) and stores them as-is because squeezing them again just wastes time. This flag
forces it to try anyway.
- `--format rust` (or `python`, or `maven`) — tells znippy the project is a Rust/Python/Maven
tree so it packs it in an ecosystem-aware way.
- `--meta-format iceberg --warehouse DIR` — writes the archive's index into an Iceberg
warehouse folder instead of inside the `.znippy` file. Advanced; ignore it to start.
- `--sign KEY --sign-cert CERT --sign-alg p256` — cryptographically signs the archive so others
can verify you made it. Ignore it to start.
## That's it
You built the tool, made a folder, compressed it into one `.znippy` file, and listed its
contents. To compress a real folder, repeat **Step 3** with your own folder after `-i` and your
own output name after `-o`.