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Omar
Omar

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I built a file watcher in Rust

#rust #cli #devtools #productivity

You know the loop.

Save. Switch to terminal. Up arrow. Enter. Wait. Switch back. Repeat forever.

I got tired of it so I built fyr, a file watcher that kills the ritual.

The basics 

fyr -w src -r "cargo run"
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Save a file inside /src, fyr runs your command. Previous run still going? It kills it first. No stale processes, no duplicate output. Just a clean run every time.

Tasks system 

fyr task add build -w src -r "cargo build --release"
fyr run build
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Save it once, run it from anywhere. No more remembering flags.

You can also drop a fyr.toml in your project and commit it, so everyone on the team gets the same setup for free:

[tasks.build]
watch = ["src"]
run = "cargo build --release"

[tasks.test]
watch = ["src", "tests"]
run = "cargo test"
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How it stacks up

Benchmarked against the popular alternatives:

Tool Startup Idle memory
fyr 219ms 7.6 MB
watchexec 238ms 13.5 MB
chokidar 501ms 37.6 MB
nodemon 528ms 41.2 MB

GitHub: https://github.com/opmr0/fyr

Would love to hear what you think, especially if you've used watchexec or cargo-watch before.

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