Tag: sysadmin

Certificate Expiry: Monitor Before the 3 AM Call

Certs expire silently. Check expiry with openssl, automate renewal checks with cron, get alerts before disaster.

Where Environment Variables Actually Live in Linux

Navigate /etc/environment, ~/.bashrc, ~/.profile, and systemd Environment=. When to use each.

Sticky Bit, Setuid, Setgid: Linux Special Permissions Explained

Understand sticky bit, setuid, and setgid: what they do, how to set them, security implications, and real-world use cases.

Is fail2ban Actually Working? Here's How to Check

Verify fail2ban is protecting you: check jails, test bans, monitor logs, common misconfiguration, and unban IPs when needed.

Diagnosing Slow Linux Boot with systemd-analyze

Use systemd-analyze to find which services are slowing down boot. Fix the bottlenecks.

Docker CMD vs ENTRYPOINT: The Final Answer

CMD and ENTRYPOINT work together. Learn the difference, exec vs shell form, and when to use the combo pattern.

SSHFS: Ditch SCP & Access Remote Files

SSHFS mounts remote filesystems over SSH so you can browse and edit files locally — faster than scp for interactive work.

How to Actually Read `systemctl status` Output

Decode systemctl status: Active state, CGroup processes, recent logs, loaded/enabled state. What each field tells you.

Is Your Linux Server Destroying Its SSD?

Check SSD health, find excessive write patterns, use noatime, move logs to tmpfs to extend lifespan.

journalctl Queries Every Sysadmin Needs

Essential journalctl commands: -u, -f, --since, -p, -k, -b, --no-pager, JSON output. The queries you need on a broken server at 2 AM.

Why Your SSH Connection Keeps Dropping

Fix SSH timeouts: ServerAliveInterval, ServerAliveCountMax, ClientAliveInterval. Understand NAT, firewalls, and TCP keepalive.

ss Is the New netstat (And It's Better)

netstat is deprecated. ss is faster, shows more, and does everything netstat did—better.