Day 8: Let’s Get Greppy – Finding Text Like a Pro in RHEL 9

[Lomanu4]

Alright, command-line comrades, it’s time we talk about someone very special…

Grep — the text detective that never sleeps.

If you’ve ever stared at a log file wondering if the answer to your issue is hiding somewhere in 3,000 lines of gobbledygook, grep is your new best friend.

? Table of Contents

• So what exactly is grep?
• Basic Syntax:
• Handy Flags for Beginners:
• Real World Use:
• Mini Mission:
• Why It Matters

So what exactly is grep?


Grep stands for Global Regular Expression Print, but don't let the fancy name scare you. It basically means: “Hey Linux, find this text for me, now, please and thank you.”


Basic Syntax:


grep "pattern" filename

Let’s say you have a file called shopping.txt and it looks like this:

apples
bananas
pineapples
chocolate bananas

Run this, and boom — it’ll spit out:

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Handy Flags for Beginners:

1. -i (ignore case)
2. -n (show line number)
3. -r (search recursively through directories)

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Now it finds both “Banana” and “banana”, and shows which line they’re on. Pretty slick.


Real World Use:

• Searching logs for errors:

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• Finding a user in /etc/passwd:

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Mini Mission:


Create a file with different fruit names. Use grep to find your favorites. Bonus points for using -i and -n.


Why It Matters


In a real-world tech job, whether you’re a sysadmin or cloud wizard, you’ll often need to extract one crucial line from a sea of chaos.

Mastering grep saves time, energy, and possibly your sanity.

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