Text Processing (Grep/Sed/Awk)

Extract specific JSON fields without installing bulky parsers

🧩 The Challenge

Dealing with JSON API responses on a minimal server where you can’t install jq is a total nightmare. I spent way too long trying to hack together regex patterns that just ended up breaking on nested fields.

💡 The Fix

Use a quick sed sequence to isolate the key value pair you need. It won’t handle complex schema changes, but it’s perfect when you just need to pull an IP or a version string from a simple response.

sed -n 's/.*"key_name": "\([^"]*\)".*/\1/p' input.json

⚙️ Why It Works

By capturing the characters between the quotes using a backreference and dropping everything else, you bypass the need for a heavy parser entirely. This saves you from hunting for dependencies on a locked-down production box.

🚀 Pro-Tip: If your JSON spans multiple lines, pipe your output through tr -d ‘\n’ before hitting sed so you have a single line to work with.

Linux Tips & Tricks | © ngelinux.com | 7/17/2026