Posts
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awk for Log Parsing: 5 Patterns You'll Actually Use
awk is perfect for parsing logs. Here are 5 patterns that handle filtering, summing, counting, splitting fields, and pretty-printing without reaching for Perl or Python.
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Why Your TLS Certificate Isn't Trusted
Incomplete cert chains, wrong order, self-signed certs. How to diagnose trust failures with openssl s_client.
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jq One-Liners Every Sysadmin Needs
jq is JSON on the command line. Here are 5 one-liners that actually solve real problems: filtering, extracting, transforming, combining, and debugging.
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Certificate Expiry: Monitor Before the 3 AM Call
Certs expire silently. Check expiry with openssl, automate renewal checks with cron, get alerts before disaster.
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xargs vs while read: Which One and When
xargs and while read both loop over input, but they handle arguments, signals, and performance differently. Here's when to use each.
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Where Environment Variables Actually Live in Linux
Navigate /etc/environment, ~/.bashrc, ~/.profile, and systemd Environment=. When to use each.
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The Firewall Rule Order That's Breaking Your Setup
Firewall rules are evaluated top-down, first match wins. One misplaced ALLOW rule silently defeats all security.
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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.
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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.
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Diagnosing Slow Linux Boot with systemd-analyze
Use systemd-analyze to find which services are slowing down boot. Fix the bottlenecks.
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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.
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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.
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