Christ Almighty I hate our industry practice of binding to some inscrutable port number on localhost. Unix domain sockets aren't that hard! They're secure against all sorts of attacks and more convenient to boot. Instead of connecting to a number, you connect to a file. An ordinary file, with an ordinary name you can mv, chmod, and rm. Boring on a good way.
So why doesn't everyone run local services over Unix sockets?
The only problems: 1) web browsers don't support AF_UNIX URI scheme, and 2) ancient versions of Java don't have built-in APIs for AF_UNIX sockets.
That's it. For these trivial reasons, we've beat our head against arbitrary opaque numbers for decades.
And so, for want of a nail, the Unix was lost.
klaushardt 3 hours ago [-]
Would be nice to have a flag to customize the URL displayed for Docker containers. I connect to my host via Tailscale, but I can’t open links with localhost. It would be helpful to have a parameter that allows us to choose a network device or specify an IP address to display.
Nice! I always forget the lsof flags and end up googling them every time. Would be cool if it could run in the system tray and show what's running on your ports at a glance. Also, the name had me thinking SonarQube at first, might be worth considering a rename to avoid the confusion.
raskrebs 1 hours ago [-]
[dead]
RonanSoleste 23 minutes ago [-]
I just have an alias in my .bashrc :)
raskrebs 10 minutes ago [-]
Try and have a look at the readme, this adds a bit more functionality. Maybe some if it you'll find useful :)
Started with the same, but found my self wanting a bit more, so just built it
raskrebs 6 hours ago [-]
I always have a bunch of local projects running, particularly during the weekend where I'm rarely working on one thing at a time. A big pain of mine was constantly running into port: Redis from one project blocking another, orphaned dev servers from old worktrees, Docker containers I forgot about. The usual fix is lsof -iTCP | grep ..., then figuring out what the PID actually is, then killing it. But I always forget the command, and it doesn’t really include all the information that I like.
So I built this lightweight CLI. Single binary, no dependencies. It shows everything listening on localhost with process names, Docker container info, clickable URLs etc.
Sure there are workarounds, but none that satisfied my need for a short, easily rememberable command. Also nothing really has the same satisfaction as running sonar kill 3000 — it just feels nice. I’ve already been approached by a few agent orchestration tools that have been struggling with the same thing. It's really useful when you have multiple agents running, but it's not built for just that use case, I have also find it handy when killing off all containers after a failed cleanup and so on. Also know that MCPs are dead and CLIs are the new thing in agentic coding, this might be a useful tool for Claude, particularly when a compose process exits before all containers are stopped.
Open for contributions, ideas and feedback.
embedding-shape 3 hours ago [-]
> I’ve already been approached by a few agent orchestration tools that have been struggling with the same thing
Wow, this says more about the agent orchestration tool ecosystem than what you might think, that they're unable to kill child processes they themselves spawn makes it seem like they have zero clue about what they're doing.
Probably why my impression always end up with "Wow, what a vibe-coded mess" when I look through the source of all these harnesses, they don't seem engineered at all.
Glad to hear! Please join the party and post any issues you have.
chwzr 3 hours ago [-]
i have this in my .zshrc which provides same functionality:
lk() {
if [ $# -eq 0 ]; then
local output=$(sudo lsof -iTCP -sTCP:LISTEN -n -P)
elif [ $# -eq 1 ]; then
local output=$(sudo lsof -iTCP -sTCP:LISTEN -n -P | grep -i --color=always $1)
else
echo "find and kill processes listening on ports. Usage: lk [pattern]"
return 1
fi
if [ -z "$output" ]; then
echo "No listening processes found."
return 0
fi
# Show header + results
echo "$(sudo lsof -iTCP -sTCP:LISTEN -n -P | head -1)"
echo "$output"
echo ""
# Extract unique PIDs (skip the header row if no grep was applied)
local pids=($(echo "$output" | awk '{print $2}' | grep -E '^[0-9]+$' | sort -u))
if [ ${#pids[@]} -eq 0 ]; then
echo "No PIDs found."
return 0
fi
echo "PIDs to kill: ${pids[*]}"
echo -n "Kill these ${#pids[@]} process(es)? [y/N] "
read -r confirm
if [[ "$confirm" =~ ^[Yy]$ ]]; then
for pid in "${pids[@]}"; do
echo "Killing PID $pid..."
sudo kill -9 $pid
done
echo "Done."
else
echo "Aborted."
fi
}
raskrebs 2 hours ago [-]
I have added quite a lot of functionality beyond listing and killing ports. Please check out the readme, it may convince you to try it out.
fionic 2 hours ago [-]
Its funny bc the title suggests a tool for listing and killing
tomcatfish 1 hours ago [-]
HN is a place where people can be expected to go beyond the title (though I like the limited script and am glad it was posted). Misleading titles are not uncommonly flagged and changed, even.
raskrebs 2 hours ago [-]
True, it was what it started as, but grew as i found my self missing features. Got a few users and now i don't want to update the name. Also easy and quick to write in the terminal
bartek_gdn 2 hours ago [-]
Why not grep the output to abother tool?
mfkrause 2 hours ago [-]
I always find myself going through my zsh history for `lsof`. Will definitely check this out, seems interesting (even though I'm generally reluctant of installing third-party tools for such jobs).
raskrebs 2 hours ago [-]
I get that, i also often install some and forgot about them. But i felt that there was a big gap in managing multiple services running on localhost. It's pretty lightweight if that helps
moezd 3 hours ago [-]
Sonar as in SonarQube? That's an interesting choice for a name :)
beart 2 hours ago [-]
How about Sonar as in SOund Navigation And Ranging?
raskrebs 2 hours ago [-]
I think a cli tool that detects objects beneath the surface is a pretty intuitive name, but i was also reluctant in the beginning. But they are pretty keen on always using the qube part, i believe theirs is sonar-qube.
frankdenbow 3 hours ago [-]
love this, happens too often
raskrebs 2 hours ago [-]
Exactly, really hates it as well. Please post any issues you may have
Bradd3rs 5 hours ago [-]
love this, i get tired of spamming lsof -i tcp:xxxx
Doublon 4 hours ago [-]
The README made me realize I just needed a simple `alias local-tcp-listeners='lsof -iTCP -sTCP:LISTEN'` in my `~/.bash_aliases` :)
deadbabe 4 hours ago [-]
Same, not sure why a whole cli app is needed.
paddim8 4 hours ago [-]
Because it gives more context. Quite obvious if you look at the readme...
raskrebs 3 hours ago [-]
Developers are nitpicky, atleast i am and i know a lot of others that are as well. So don't underestimate the value of a nice tool with good developer experience, one that's intuitive, clean and easy to use means a lot when juggling so many things during a workday. So having a clean and light implementation to make job even easier is in my opinion worth it (and thus needed) :)
3 hours ago [-]
raskrebs 3 hours ago [-]
True, but as i write their are workarounds, the problem is that they are unintuitive, difficult to remember and don't provide all that much usability beyond listing. So these lack useful features like getting process stats, killing ports easily without having to remember the the pid after lsof and so on. I often have to kill multiple process at once after a failed cleanup. If you are into agentic coding, then having your agent create a profile for all the processes it stats, which it can easily kill of when finished is a lot easier for me atleast.
Some features on the way are: next available port; wait (wait for a host to return a successful health check before proceeding - good for migrations etc.). And lots more. It's not just about listing running ports, but a tool for managing them.
But to each their own, that's what's lovely about the many options available. But if you have anything in relation to this you think is neat, feel free to open an issue. It may be able to convince you that a simple alias won't suffice.
raskrebs 5 hours ago [-]
Glad to hear! Have quite a few ideas in mind so keep an eye out for some updates (one of the ideas is an easy update command). There's a couple of open enhancement ideas as well. Feel free to add any or contribute.
takahitoyoneda 3 hours ago [-]
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olivercoleai 2 hours ago [-]
[dead]
Servant-of-Inos 6 hours ago [-]
[dead]
Rendered at 16:14:45 GMT+0000 (Coordinated Universal Time) with Vercel.
So why doesn't everyone run local services over Unix sockets?
The only problems: 1) web browsers don't support AF_UNIX URI scheme, and 2) ancient versions of Java don't have built-in APIs for AF_UNIX sockets.
That's it. For these trivial reasons, we've beat our head against arbitrary opaque numbers for decades.
And so, for want of a nail, the Unix was lost.
https://github.com/RasKrebs/sonar/issues
Started with the same, but found my self wanting a bit more, so just built it
So I built this lightweight CLI. Single binary, no dependencies. It shows everything listening on localhost with process names, Docker container info, clickable URLs etc.
Sure there are workarounds, but none that satisfied my need for a short, easily rememberable command. Also nothing really has the same satisfaction as running sonar kill 3000 — it just feels nice. I’ve already been approached by a few agent orchestration tools that have been struggling with the same thing. It's really useful when you have multiple agents running, but it's not built for just that use case, I have also find it handy when killing off all containers after a failed cleanup and so on. Also know that MCPs are dead and CLIs are the new thing in agentic coding, this might be a useful tool for Claude, particularly when a compose process exits before all containers are stopped.
Open for contributions, ideas and feedback.
Wow, this says more about the agent orchestration tool ecosystem than what you might think, that they're unable to kill child processes they themselves spawn makes it seem like they have zero clue about what they're doing.
Probably why my impression always end up with "Wow, what a vibe-coded mess" when I look through the source of all these harnesses, they don't seem engineered at all.
https://github.com/clutchski/dotfiles/blob/main/home/bin/por...
For the even less patient there's also this (not mine): https://github.com/jkfran/killport
Some features on the way are: next available port; wait (wait for a host to return a successful health check before proceeding - good for migrations etc.). And lots more. It's not just about listing running ports, but a tool for managing them.
But to each their own, that's what's lovely about the many options available. But if you have anything in relation to this you think is neat, feel free to open an issue. It may be able to convince you that a simple alias won't suffice.