# just-bash by Vercel Labs

11 Hacker News commenters recommended just-bash by Vercel Labs and 9 criticized it, November 2025 to November 2026. It was recommended in 5 of 13 months.

**Verdict:** A sandboxed bash-like shell in TypeScript for AI agents, fast because it starts no processes. Critics say its incompatibilities with real bash make it leaky.

## Why people recommend it

- Lightweight, fast sandbox for agents (3 comments): "In practice it is actually extremely fast because there is no process fork." ([source](https://news.ycombinator.com/item?id=47170565)) "you can give it an lightweight secure execution environment like just-bash" ([source](https://news.ycombinator.com/item?id=49907920)) "Clever use of just-bash to avoid the sandbox cold-start problem" ([source](https://news.ycombinator.com/item?id=47636599))
- Clever, cool approach overall (4 comments): "Clever use of just-bash to avoid the sandbox cold-start problem" ([source](https://news.ycombinator.com/item?id=47636599)) "I love the approach of just bash as well. Super cool!" ([source](https://news.ycombinator.com/item?id=47178679)) "it worked very well and was undeniably pretty cool" ([source](https://news.ycombinator.com/item?id=47168860))
- Works reliably in practice (2 comments): "In practice it works great. I haven't seen a failed command in a while" ([source](https://news.ycombinator.com/item?id=47170632)) "it worked very well and was undeniably pretty cool" ([source](https://news.ycombinator.com/item?id=47168860))

## What people warn about

- Incompatible with real bash behavior (4 comments): "the issue is to make the tools compatible with the official tools otherwise you will get odd behaviour" ([source](https://news.ycombinator.com/item?id=47167646)) "I don't think the current incompatibilities can be worked around." ([source](https://news.ycombinator.com/item?id=47169063)) "It was never trained on an incompatible, partial implementation." ([source](https://news.ycombinator.com/item?id=47167101))
- Forked and rebranded; controversial (3 comments): "Is this tactic of forking and rebranding some sort of open source embrace, extend, extinguish thing?" ([source](https://news.ycombinator.com/item?id=47392647)) "the reasons for the fork seem to be largely LLM hallucinated, I think it counts as a slop-fork" ([source](https://news.ycombinator.com/item?id=47392696)) "Vercel have been reimplementing Bash and dozens of other common Unix tools in TypeScript" ([source](https://news.ycombinator.com/item?id=47322592))
- Unclear benefit over sandboxed bash (2 comments): "I suspect that something like this will be a far too leaky abstraction." ([source](https://news.ycombinator.com/item?id=47169690)) "Not sure why I would ever want to use this over bash in a sandboxed VM." ([source](https://news.ycombinator.com/item?id=47174530))

## Alternatives hackers recommend

- [Bash](https://hackerapproved.com/p/bash.md): 171 recommend
- [PowerShell](https://hackerapproved.com/p/powershell.md): 156 recommend
- [fish shell](https://hackerapproved.com/p/fish-shell.md): 97 recommend
- [Nushell](https://hackerapproved.com/p/nushell.md): 92 recommend
- [zsh](https://hackerapproved.com/p/zsh.md): 52 recommend

## Cite as

Hacker Approved, "just-bash by Vercel Labs", https://hackerapproved.com/p/just-bash/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).