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Thu Kha Kyawe
Thu Kha Kyawe

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11.String Replacement

Lab Information

Within the Stratos DC, the backup server holds template XML files crucial for the Nautilus application. Before utilization, these files require valid data insertion. As part of routine maintenance, system admins at xFusionCorp Industries employ string and file manipulation commands.

Your task is to substitute all occurrences of the string Text with Submarine within the XML file located at /root/nautilus.xml on the backup server.

Lab Solutions

🧭 Part 1: Lab Step-by-Step Guidelines

🔹 Step 1: Log in to Jump Host

ssh thor@jump_host.stratos.xfusioncorp.com

Password:

mjolnir123

🔹 Step 2: SSH into Backup Server

ssh clint@stbkp01.stratos.xfusioncorp.com

Password:

H@wk3y3

🔹 Step 3: Switch to root

sudo -i
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🔹 Step 4: Replace all occurrences of Text with Submarine

sed -i 's/Text/Submarine/g' /root/nautilus.xml
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🔹 Step 5: Verify replacement

grep Text /root/nautilus.xml
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This should return no output.

Then confirm:

grep Submarine /root/nautilus.xml

You should see occurrences of Submarine.

✅ Final Checklist

✔ Executed on Backup Server only
✔ Modified file: /root/nautilus.xml
✔ All Text replaced with Submarine
✔ No remaining Text strings
✔ Verified successfully


🧠 Part 2: Simple Step-by-Step Explanation (Beginner Friendly)

🔹 What is the task?

Inside this file:

/root/nautilus.xml

There are multiple instances of the word:

Text

We must replace every occurrence with:

Submarine

🔹 Why use sed?

sed is a stream editor used for:

Searching

Replacing

Editing files directly from the command line

🔹 Breaking down the command
sed -i 's/Text/Submarine/g' file
Part Meaning
-i Edit file in place
s Substitute
Text Word to find
Submarine Replacement word
g Replace all occurrences in each line

🔹 Why use g?

Without g, only the first occurrence in each line would be replaced.

With g, every occurrence is replaced.

🔐 Real-World Context

This simulates:

Updating template files

Injecting correct configuration values

Automating repetitive file edits

String replacement using sed is a common DevOps and sysadmin task.


Resources & Next Steps
📦 Full Code Repository: KodeKloud Learning Labs
📖 More Deep Dives: Whispering Cloud Insights - Read other technical articles
💬 Join Discussion: DEV Community - Share your thoughts and questions
💼 Let's Connect: LinkedIn - I'd love to connect with you

Credits
• All labs are from: KodeKloud
• I sincerely appreciate your provision of these valuable resources.

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