Tag: bash

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 variables split on IFS, breaking loops and file operations. Always quote vars. Here's why.

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 silently fails in subshells, pipes, and conditionals. Learn the gotchas and 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.

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.

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.

Why Your Cron Job Is Failing Silently

PATH is different in cron, stdout is muted, and MAILTO breaks silently. Learn cron traps and how to debug them.

find Flags You Keep Forgetting

Practical find command examples: -mtime, -newer, -type, -exec vs xargs, -not, size filters. The patterns you google every time.

Why kill -9 Is the Wrong Default

Signals explained: SIGTERM vs SIGKILL, graceful shutdown, and when to actually use kill -9.