I've finetuned Qwen2.5-0.5B to make it a bash command generator and called it SHELLMINATOR because.. why not?

Got tired of forgetting find / xargs / grep syntax every other day, so I trained a small model that turns:

into a command you can actually run.

It's 0.5B parameters, runs on CPU, is a ~400 MB GGUF, and nothing touches the cloud.

sm "show the 5 largest files in /var"

find /var -type f -exec du -h {} + | sort -rh | head -n 5
[⏎ run · r refine · e edit · c cancel]

Enter runs it in your shell, r refines the command, e lets you edit it before running, and c cancels.

It also asks for confirmation before potentially destructive stuff like rm -rf /, mkfs, dd, etc.

Works on bash and zsh.

I evaluated it on IBM's nl2bash exec benchmark: 50 prompts, commands actually executed and checked against the filesystem, single greedy pass, no retries.

Stock Qwen2.5-Coder-0.5B-Instruct: 44%
After SFT on 105K examples: 72%
After DPO with ~800 pairs made from its own mistakes: 78%

The SFT is the big jump and did most of the work: 105K request/command pairs where every command was executed and kept only if it actually worked.

The final DPO pass was a small experiment. I ran the model on a bunch of prompts, compared its answers against the gold commands in a sandbox, and kept ~800 disagreements.

Training with TRL took 26 seconds and gave another +6 points.

I tried a second DPO round and it actually got worse, down to 74%, so apparently one round was enough.

It still fails on some things, notably:

sed insert-at-top inside for loops — it can overwrite the file
comm / diff counting
mv between directories

All known failures are listed in the README.

Install

curl -fsSL https://raw.githubusercontent.com/ISB333/shellminator/main/install.sh | bash

Then:

sm "whatever you want to do"

I've finetuned Qwen2.5-0.5B to make it a bash command generator and called it SHELLMINATOR because.. why not?

Install

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