Tag: linux

What is lost+found and why does it exist? fsck puts recovered file fragments there after a crash — and no, you can't delete it.

AV vs EDR — traditional antivirus signatures vs behavioral endpoint detection. What each catches, what it misses, and what you actually need.

Packages have been kept back during apt upgrade — what it means, why it happens, and how to safely install or hold those packages.

UFW makes iptables manageable — allow and deny rules, app profiles, default policies, and the 5-minute setup for any new Linux server.

ulimit and cgroups v2: set per-process CPU, memory, and file limits, use systemd slice controls, and keep one runaway service from killing your server.

Containers share the kernel; VMs have their own. Understand the isolation trade-offs, overhead differences, and when to use which.

Decode the postgresql:// connection string — host, port, database, SSL mode, and the gotchas that cause connection refused at deploy time.

echo is convenient but inconsistent across systems; printf is portable and precise — know when to use each and avoid the gotchas.

LXC/LXD runs full Linux environments in lightweight containers — faster to spin up than VMs and perfect for home lab service isolation.

Update one package with apt without upgrading everything else — the exact flag, version pinning, held package handling, and the apt vs apt-get distinction that trips people up.

Squeeze every MB/s from WireGuard: MTU sizing, GSO/GRO CPU offloading, AllowedIPs routing, PersistentKeepalive tradeoffs, and iperf3 benchmarks included.

FRR vs BIRD: two open-source routing daemons compared for BGP, OSPF, and home-lab dynamic routing. Which one belongs in your stack?