Bug Run: Fix the Broken Commands
Ages 8+BeginnerFree · no ads · no sign-upUpdated November 2026
Spot it. Fix it. Send it home!
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About Bug Run
Each bug carries a broken command. Spot the mistake, type the command the right way, and the bug tumbles back home.
Bug Run uses only commands from the free lessons, level by level. Play it free in your browser, with no ads and no sign-up.
Guide How to play
- Pick a level and press Play. Friendly bugs walk toward PlayType's door, each with a command on its sign.
- Every command on a sign has one mistake: a swapped letter, a missing space, a dash that is not there. Find it first.
- Type the command the right way. The lit sign is the bug to fix, the one nearest the door. Capital letters do not matter, as in PowerShell.
- A wrong key is not typed. Copy the mistake and PlayType says so; stay stuck and the next letter shows as a hint.
- Fix every bug in the level to win. A bug that reaches the door gets in, so keep an eye on the lane.
Bug Run practises spotting the one wrong letter, space or dash in a command, and entering it right. Reading a command closely, letter by letter, is how you fix red text in a real terminal, too: the computer did exactly what it was told, so the mistake is in what was typed.
Levels The bugs in each level
Every bug below fails on the practice terminal, and its fix works, from your home folder or from Documents. Try both and read the red text the bug gives.
| The bug | The fix | What was wrong |
|---|---|---|
dri | dir | Two letters swapped places: it is dir. |
cdDocuments | cd Documents | A space goes between the command and the folder. |
cd Documnets | cd Documents | The folder name was spelt wrong: Documents. |
cd Pictres | cd Pictures | Pictures was missing its u. |
dirDesktop | dir Desktop | dir needs a space before the folder. |
dir Dowloads | dir Downloads | Downloads was missing an n. |
dr Documents | dir Documents | dir lost its i. |
cd. . | cd .. | The two dots stay together, after a space. |
cd my project | cd my-project | The folder name has a dash, not a space. |
cd my-project\imagess | cd my-project\images | images had one s too many. |
From the lessons up to lesson 7, Level 1 test: Find the Cat.
| The bug | The fix | What was wrong |
|---|---|---|
pdw | pwd | p-w-d: print working directory. |
mkdri games | mkdir games | m-k-d-i-r: make directory. |
mkdir my games | mkdir my-games | A space splits a name in two: use a dash. |
mkdirgames | mkdir games | A space goes after the command. |
ecoh hi | echo hi | echo was spelt ecoh. |
cta notes.txt | cat notes.txt | It is cat, not cta. |
cat note.txt | cat notes.txt | The file is notes, with an s. |
cat notes,txt | cat notes.txt | A dot goes before the ending, not a comma. |
cat notes.tx | cat notes.txt | The ending is .txt, all three letters. |
clss | cls | cls has just one s. |
cat lsit.txt | cat list.txt | list was spelt lsit. |
From the lessons up to lesson 15, Level 2 test: Command Captain.
| The bug | The fix | What was wrong |
|---|---|---|
copy notes.txt | copy notes.txt backup.txt | copy needs two names: what, then where. |
cpoy notes.txt backup.txt | copy notes.txt backup.txt | copy was spelt cpoy. |
ren list.txt | ren list.txt shopping.txt | ren needs the old name, then the new one. |
rm junk\old.tx | rm junk\old.txt | The ending is .txt. |
rm notes.txt WhatIf | rm notes.txt -WhatIf | -WhatIf needs its dash. |
rm notes.txt -WhatIff | rm notes.txt -WhatIf | WhatIf has just one f. |
dir Name | dir -Name | -Name is a parameter: it needs a dash. |
help cpoy | help copy | help can only explain copy if copy is spelt right. |
Get-Alais ls | Get-Alias ls | Alias was spelt Alais. |
GetAlias ls | Get-Alias ls | A dash joins Get and Alias. |
pyhton hello.py | python hello.py | python was spelt pyhton. |
python helo.py | python hello.py | The file is hello.py, with two Ls. |
python hello | python hello.py | Give the whole name, with .py on the end. |
From the lessons up to lesson 24, Level 3 test: Safe Hands.
The fourth level, Every bug, mixes all three. Not sure what a command does? Look it up in the PowerShell cheat sheet or the Command Book.
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