Tag: linux

SSH Hardening: Lock Down Remote Access Without Locking Yourself Out

Harden SSH properly: disable password auth, switch to Ed25519 keys, configure sshd_config, set up SSH certificates with step-ca, add 2FA, and configure ProxyJump for bastion hosts.

trap in Bash: Clean Up When Your Script Dies

Use trap EXIT to clean up temp files, INT/TERM for graceful shutdown, and ERR for errors. Stop your bash scripts from leaving messes when they die.

Debugging Bash Scripts: set -x and Beyond

set -x prints every command before it runs. Add PS4 for context. Use trap for cleanup. Here's the toolkit every bash debugger needs.

Word Splitting: The Bash Gotcha That Corrupts Filenames

Unquoted bash variables split on IFS and quietly break loops, file ops, and filenames with spaces. Here's why it happens and how to always quote right.

String Manipulation in Bash (Without sed or awk)

Bash has built-in string operations: substring extraction, find-replace, case conversion, and trimming. You don't need sed for basic text work.

bash `set -e` Doesn't Work Like You Think

set -e looks bulletproof, but it slips right through pipes, command substitution, and conditionals. The bash gotchas that bite at 2 AM, and how to fix them.

Bash Arithmetic Without bc

Bash has built-in arithmetic. You don't need bc for 90% of math. Here's how to do it right.

Linux Audit Log: What's Really Happening on Your Server

auditd logs every system call, file access, and command run on your Linux server. Learn ausearch, aureport, and how to write audit rules that catch it.

Ventoy: Boot Any OS, Any Time

Ventoy turns any USB drive into a multi-boot drive — drop ISOs on it and boot any OS without re-flashing the drive each time.

Bash Strict Mode: set -euo pipefail Explained

set -euo pipefail makes your bash scripts fail fast instead of silently. Here's what each flag does and why they matter.

The sudoers Mistake Everyone Makes Once

Never edit /etc/sudoers directly. One syntax error locks everyone out. Use visudo, understand NOPASSWD risks.

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.