Linux Applications Programming by Example: The Fundamental APIs (2nd Edition)
13 by teleforce | 0 comments on Hacker News.
13 by teleforce | 0 comments on Hacker News.
Friday, March 20, 2026
New top story on Hacker News: Show HN: Red Grid Link – peer-to-peer team tracking over Bluetooth, no servers
Show HN: Red Grid Link – peer-to-peer team tracking over Bluetooth, no servers
8 by redgridtactical | 3 comments on Hacker News.
I go on a lot of backcountry trips where I barely get cell service. If my group splits, nobody knows knows where anyone is until you regroup at camp or at your destination. You can buy Garmin radios or try to set up an ATAK, but ATAK is Android-only and assumes you have a TAK Server running somewhere to make use of all of the functionality. Cool tools themselves, but expensive to set up correctly. I just wanted two iPhones to share their location directly over Bluetooth when cell coverage was lacking. Red Grid Link does that. Start a session, and anyone nearby running the app shows up on your offline map. When they walk out of range their marker stays as a "ghost" that slowly fades. The hard part was making sync reliable over BLE. The connections drop all the time. Someone turns a corner, walks behind a vehicle, whatever. I built a CRDT sync layer (LWW Register + G-Counter) so there's never merge conflicts. Each update is just under 200 bytes (from what I have tested so far). When a user/teammate disappears the app does exponential backoff from 2 to 30 seconds before giving up and marking them as a ghost. Everything is encrypted (AES-256-GCM, ECDH P-256 key exchange per peer pair). Sessions can require a PIN or QR code to join. It also offers offline topo maps with MGRS grid coordinates, same system as in my other app, Red Grid MGRS. The app is free, and I'm looking for some honest feedback from other real-world users. Let me know if you have any questions!
8 by redgridtactical | 3 comments on Hacker News.
I go on a lot of backcountry trips where I barely get cell service. If my group splits, nobody knows knows where anyone is until you regroup at camp or at your destination. You can buy Garmin radios or try to set up an ATAK, but ATAK is Android-only and assumes you have a TAK Server running somewhere to make use of all of the functionality. Cool tools themselves, but expensive to set up correctly. I just wanted two iPhones to share their location directly over Bluetooth when cell coverage was lacking. Red Grid Link does that. Start a session, and anyone nearby running the app shows up on your offline map. When they walk out of range their marker stays as a "ghost" that slowly fades. The hard part was making sync reliable over BLE. The connections drop all the time. Someone turns a corner, walks behind a vehicle, whatever. I built a CRDT sync layer (LWW Register + G-Counter) so there's never merge conflicts. Each update is just under 200 bytes (from what I have tested so far). When a user/teammate disappears the app does exponential backoff from 2 to 30 seconds before giving up and marking them as a ghost. Everything is encrypted (AES-256-GCM, ECDH P-256 key exchange per peer pair). Sessions can require a PIN or QR code to join. It also offers offline topo maps with MGRS grid coordinates, same system as in my other app, Red Grid MGRS. The app is free, and I'm looking for some honest feedback from other real-world users. Let me know if you have any questions!
Thursday, March 19, 2026
Wednesday, March 18, 2026
Tuesday, March 17, 2026
Monday, March 16, 2026
New top story on Hacker News: Show HN: Trackm, a personal finance web app
Show HN: Trackm, a personal finance web app
5 by iccananea | 0 comments on Hacker News.
I built this as a personal finance app that allows me to see how my recurring incomes and expenses will affect my network over the years. So trackm can show up to 4 years in the future and track when your accounts will go negative given you expenses and incomes. I've been dogfooding it for the past 10 days, fixing issues I find from my day-to-day use and now it's at a point where I'm comfortable sharing it with others. The app is free for 30 days, after which it goes into read-only mode. Paying the one-time license fee unlocks it forever.
5 by iccananea | 0 comments on Hacker News.
I built this as a personal finance app that allows me to see how my recurring incomes and expenses will affect my network over the years. So trackm can show up to 4 years in the future and track when your accounts will go negative given you expenses and incomes. I've been dogfooding it for the past 10 days, fixing issues I find from my day-to-day use and now it's at a point where I'm comfortable sharing it with others. The app is free for 30 days, after which it goes into read-only mode. Paying the one-time license fee unlocks it forever.