Tag: linux

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.

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.

Where Environment Variables Actually Live in Linux

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

The Firewall Rule Order That's Breaking Your Setup

Firewall rules are evaluated top-down, first match wins. One misplaced ALLOW rule above your denials silently defeats all your security. Here's the fix.

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.