swp

Find what's holding a port, and kill it.

There are two ways in.

1. The picker, for when you want to look around — arrow keys, a fuzzy filter across every column, and a kill that asks first:

swp

2. A query, for when you already know what you want. It answers on stdout and exits, so it composes:

$ swp -p 3000
PORT    PID  USER   MEM  UP  NAME  COMMAND
3000  49649  dsaad  66M  1d  bun   --hot scripts/serve.ts

That is the whole rule: a query answers and exits, a bare swp opens the picker. So swp 3000 works in a pipeline with no flag for it, while swp alone browses.

Written in pure Swift with no lsof, no ps, and no subprocesses — it reads the kernel's own process and socket tables. A full scan of a thousand processes takes about 12 ms, which is what lets the picker refresh itself while you look at it.

brew install dsaad68/tap/swp

Upgrade later with brew upgrade swp. The macOS bottle is a universal binary (Apple Silicon and Intel); Linux is x86_64.

Requires a Swift 5.9+ toolchain.

git clone https://github.com/dsaad68/swp && cd swp
just install          # release build, symlinked into ~/.local/bin (no sudo)

Make sure ~/.local/bin is on your PATH. To run from a clone without installing: just swp, just swp 3000, just swp -i node.

swp                   # browse everything holding a port
swp 3000              # print what's on port 3000
swp node              # print processes named — or running — node
swp -k 3000           # kill what's on 3000 (asks first)
swp --cpu --top 5     # the five busiest processes
swp -a                # browse every process, port or not
swp -i 3000           # open the picker on a query instead

j/k move and x kills — deliberately never the other way round. A tool that kills on the twin of the up-arrow will one day kill the wrong thing.

The guide covers everything: the query language, every flag, reading each column, killing safely, scripting with --json, and what swp cannot see. Releasing documents the tag-driven pipeline. CHANGELOG.md tracks releases.

Without root, macOS will not open another user's file descriptors, so the ports, memory and CPU of other users' processes are invisible. Their rows are there; those columns are not. sudo swp sees everything, and the picker says so in its footer rather than leaving you to wonder why sudo lsof disagrees.

There is no per-process network or GPU figure available to a program like this on either platform — both need private frameworks or a root packet capture. swp --net and swp --gpu explain that rather than failing as unknown options. Details in the guide.

just build    just test    just integration
just check       # format + lint + test, the way CI does
just linux-test  # the same, for Linux, in a container (needs Docker)
just preflight   # both of the above — run this before tagging

swp's Linux scanner is behind #if !canImport(Darwin), so a macOS build never compiles it. Run just linux-test before releasing; docs/releasing.md explains why that is not hypothetical.

swpCore is everything reasonable without a terminal — the scanners, the query language, formatting, the killer — and has no dependency on the executable, so it is testable alone. swp is the terminal: raw mode, key decoding, frames, the picker. Frames are a pure function of state and size, so tests assert on whole rendered frames rather than on the pieces that make one.

There are no third-party dependencies, and that is deliberate — see the guide.

lsof -i :3000 answers the same question and takes longer to start than this takes to run. fkill and fuser are close cousins.

The chrome — rounded frame, wordmark, fuzzy filter box — is deliberately the same shape as termdown, in a different palette: teal → amber rather than blue → mauve, so the half-second of "which one did I just launch" never happens.

MIT © 2026 Daniel Saad