Text Processing (Grep/Sed/Awk)

Stop editing config files manually when you need to swap a variable

🧩 The Challenge

Dealing with a massive config file where the same parameter appears in different contexts is a nightmare. I once spent an hour fixing a load balancer config only to realize I had missed the one instance that was actually causing the failure.

💡 The Fix

Use sed to perform an in-place search and replace across the entire file so you don’t have to hunt down every single line manually. It’s safer and way faster than trying to play find-the-needle in vim.

sed -i 's/OLD_VALUE/NEW_VALUE/g' /etc/app/config.conf

⚙️ Why It Works

By passing the -i flag, sed edits the file directly, and the ‘g’ at the end ensures it replaces every occurrence on a line, not just the first one. It saves you from manual intervention errors.

🚀 Pro-Tip: Always run it without -i first to preview the changes in your terminal before you pull the trigger.

Linux Tips & Tricks | © ngelinux.com | 10/2/2026