Tag: sysadmin

lsof: The Tool That Shows You Everything

Master lsof to find port conflicts, trace deleted files eating disk, and debug network connections.

Docker Exit Codes: Why Your Container Keeps Restarting

Decode Docker exit codes: 0 (success), 1 (app error), 125/126/127 (Docker errors), 137 (OOM), 143 (SIGTERM). Debug restarts in minutes.

CPU and I/O Priority with nice and ionice

Manage Linux process priority with nice (CPU) and ionice (I/O). Learn priority levels, renice running processes, and avoid tanking server performance.

Linux File Descriptor Limits: When 1024 Isn't Enough

File descriptors and why that 1024 limit kills your server. How to check, raise, and debug fd exhaustion.

Why Your Docker Logs Are Eating Your Disk

Docker's default JSON logging driver writes unbounded logs to disk. Learn how to set log rotation and reclaim your storage.

The `at` Command: One-Time Scheduled Tasks in Linux

Schedule one-off Linux tasks with `at` instead of cron. Learn syntax, queue management, batch jobs, and when to use it for delayed reboots and reminders.

Why Your Docker Container Ignores Ctrl+C

PID 1 doesn't receive signals by default. Learn why Ctrl+C fails in containers and fix it with tini or exec form CMD.

Optimize Ubuntu Logs: btmp Log Rotation

btmp logs failed logins and grows forever on internet-facing servers. Set up logrotate to keep it under control before your disk fills up.

Finding the PID of a Process Using a Specific Port in Linux

Something's squatting on port 8080 and you need to know what. ss, lsof, and fuser one-liners to find and kill the culprit fast.

Essential Linux Commands for Daily Use

The Linux commands every sysadmin reaches for daily — file ops, process management, networking, and text manipulation you can't live without.

Mastering xargs in Linux

xargs turns stdin into arguments — build complex pipelines, run parallel jobs, and handle filenames with spaces without breaking everything.

LVM The Linux Sysadmin’s Guide to Flexible Storage

LVM lets you resize volumes, add disks, and take snapshots without repartitioning — PVs, VGs, and LVs explained with real commands.