Tag: bash

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.

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

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.

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

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

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

awk is perfect for parsing logs. 5 patterns for filtering, summing, counting, splitting fields, and reformatting, no Perl or Python required.

jq is JSON on the command line. Here are 5 one-liners that actually solve real problems: filtering, extracting, transforming, combining, and debugging.

xargs and while read both loop over input, but they handle arguments, signals, and performance differently. Here's when to use each.

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

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