Exercise: Sort the Downloads Folder

Sort a messy Downloads folder of photos, songs, a lease, a resume and a year of receipts into folders with mkdir, mv and cp, wildcards and braces, without replacing a thing, and let a check script tell you what's done.

Apprentice · Unix · Linux · Updated

Everyone has a Downloads folder like this one: phone photos, a couple of screenshots, songs, a lease, a resume, school papers and a whole year of receipts, all in one pile of 30 files. Your job is to sort it into folders, a few commands at a time, without losing or replacing anything on the way. There's one trap in the pile: a file that has the same name as one already sorted. A check script looks at the folder when you're done and tells you which parts are right.

Before you start

You need a terminal: the Terminal app on a Mac, or Ubuntu on Linux or in WSL on Windows. The check runs with bats, the program that ran your earlier exercise checks. If bats --version doesn't print a version number yet, install it:

sudo apt install bats       # Ubuntu, and Ubuntu in WSL
brew install bats-core      # a Mac, with Homebrew

sudo asks for your password, the one you use to sign in; nothing shows on the screen while you type it.

Get the exercise code

Open this lesson's GitHub repository, github.com/ask-codey/exercise-bash-sort-the-downloads-folder, also linked from the Exercise box beside the lesson. Click Code, then Download ZIP, and unzip it into your terminal-practice folder. Or clone it with Git.

The folder holds:

  • downloads/: the pile to sort. Every file is a small stand-in with one line of text, not a real photo or PDF. downloads/documents/ already holds last year's lease.pdf.
  • check.bats: the check. You don't need to change it.
  • README.md: the job, in short.

What to do

Open a terminal, cd into the exercise folder (the one with check.bats in it), then cd downloads and look around with ls. Then sort the pile:

  1. Make the folders. photos and music in downloads, and receipts with four folders inside it, q1 to q4, one for each quarter of the year.
  2. The bus pass. The screenshot from October 2, Screenshot 2026-10-02 at 09.14.55.png, is your bus pass. Put it in documents, named bus-pass.png.
  3. Photos. Every other .jpg and .png goes in photos.
  4. Music. Every .mp3 goes in music.
  5. Receipts. Each receipt goes in its quarter's folder: January to March in q1, April to June in q2, July to September in q3, and October to December in q4. The month is the number after 2026- in the name, as in receipt-2026-04-22.pdf.
  6. The new lease. documents already has last year's lease.pdf. Keep it, and put the new lease.pdf beside it, named lease-2026.pdf.
  7. Your resume. You're about to edit it, so keep a copy first: resume.docx.bak, beside resume.docx. Both go in documents.
  8. The rest. The other .pdf files go in documents. When you're done, nothing is left loose in downloads: only folders.

Use the terminal for all of it, and don't edit, empty or delete any file.

Check your work

From the exercise folder (not from inside downloads):

bats check.bats

At first almost every check fails. That's expected: each part you finish turns its check into a ✓. A failing check says what's still out of place and gives a hint, for example These songs aren't in music yet: downloads/podcast-episode-12.mp3 downloads/rainy-day-mix.mp3 downloads/song-for-the-road.mp3. One mv with *.mp3 moves them all.

Hints

  • Echo first. Before any mv with a wildcard, echo the same pattern and read the list (Wildcards: *, ? and [ ]). If the list is wrong, the move would be wrong too.
  • Order matters. The receipts, the bus pass and the new lease are files a broad pattern such as *.pdf or *.png would also catch. Sort the special ones first.
  • One folder per quarter, one line. mkdir -p makes a folder and the folders around it, and braces name all four quarters at once (Brace Expansion: Twelve Folders in One Line).
  • A quarter is three months. [ ] matches one character from a range, so a single pattern can pick out three months' receipts.
  • Nothing gets replaced. mv -i asks before it replaces a file, and mv -n never does (Copy, Move and Rename: cp and mv). If last year's lease does get replaced, there's no undo: download the exercise again and start over.
  • Moved something to the wrong folder? Move it again: mv works from any folder to any other. An extra folder made by mistake does no harm, because the check only looks at the ones it names.

When you're done

Every check passes:

check.bats
 ✓ the downloads folder is still here
 ✓ 1) photos, music and documents are folders in downloads
 ✓ 2) receipts has a folder for each quarter, q1 to q4
 ✓ 3) all nine photos are in photos
 ✓ 4) the bus pass is documents/bus-pass.png
 ✓ 5) all three songs are in music
 ✓ 6) every receipt is in its quarter's folder
 ✓ 7) last year's lease is still documents/lease.pdf
 ✓ 8) the new lease is documents/lease-2026.pdf
 ✓ 9) resume.docx and its backup, resume.docx.bak, are in documents
 ✓ 10) the other documents are in documents
 ✓ 11) nothing is left loose in downloads

12 tests, 0 failures

Now count your commands. How many did the whole pile take, and how many would it have taken with one mv for each of its 30 files?

Submit your exercise

The exercise is how you finish this lesson. When your work is done, put it on GitHub in a repo of your own, then submit that repo's address here.

  1. On GitHub, click +, then New repository. Name it (for example exercise-bash-sort-the-downloads-folder), choose Public, and click Create repository. Leave out the README: your folder already has one.

  2. In a terminal in your exercise folder (Ubuntu in WSL on Windows), send your work to your new repo. If you downloaded the ZIP:

    git init -b main
git add .
git commit -m "My solution"
git remote add origin https://github.com/your-name/exercise-bash-sort-the-downloads-folder.git
git push -u origin main

    If you cloned the starter instead, point your copy at your own repo, then commit and push:

    git remote set-url origin https://github.com/your-name/exercise-bash-sort-the-downloads-folder.git
git add .
git commit -m "My solution"
git push -u origin main

  3. Paste your repo's address, such as https://github.com/your-name/exercise-bash-sort-the-downloads-folder, into Submit your exercise on this page. The site checks that the repo is public and holds your commits, and then the lesson is complete.

Changed something after you submitted? Push it, and submit again: your latest submission is the one that counts.

So what

Sorting a folder of 30 files, or 3,000, is the same handful of commands: make the folders, check a pattern with echo, move. It's the everyday cleanup that IT technicians, photographers and anyone with a full Downloads folder do, in minutes instead of an afternoon.

Key terms

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