Jenkins Runs Commands For Me

Before Jenkins:

• Engineer runs commands manually


• Forgets steps


• Makes mistakes


• Cannot repeat reliably

With Jenkins:

• Commands are written once
  


• Jenkins runs them the same way every time
  


• Anyone can click Build Now
  

🛠 Task Rules (IMPORTANT)

• ❌ No copy–paste


• ✅ Students type each line
  


• ✅ After each line, explain why it exists
  

🧩 Step 1: Create Freestyle Job

1. Open Jenkins:
   
   http://localhost:9090




2. Click New Item




3. Job name:
   
   

devops-first-script

1. Select Freestyle project
   


2. Click OK
   

🧩 Step 2: Add Shell Build Step

• Scroll to Build
  


• Click Add build step
  


• Choose Execute shell
  

✍️ Step 3: Write This Script (Line by Line)

Line 1

echo "Hello from Jenkins"

Why?

• 
  echo prints text


• Proves Jenkins can execute commands
  


• First validation Jenkins is working

Line 2

whoami

Why?

• Shows which user Jenkins runs as


• Important for permissions (DevOps reality)


• Explains why some commands fail later

Line 3

pwd

Why?

• Shows where Jenkins runs
  


• Introduces the concept of workspace
  


• Jenkins does NOT run in your home folder

Line 4

ls

Why?

• Lists files in workspace


• Shows workspace starts empty
  


• Important before cloning repos later

Line 5

echo "This file was created by Jenkins" > jenkins.txt

Why?

• Jenkins creates files just like a human


• Demonstrates automation creates artifacts


• 
  > redirects output into a file

Line 6

cat jenkins.txt

Why?

• Confirms file exists


• Verifies Jenkins work visually


• Basic troubleshooting skill

Line 7

echo "Script completed successfully"

Why?

• Clear log message


• Professional habit in CI/CD


• Helps debugging later

▶️ Step 4: Run the Job

• Click Save
  


• Click Build Now
  


• Open Console Output
  

✅ What Should See

• Text printed


• Username


• Jenkins workspace path


• File created


• File content displayed

🧠 DevOps Concepts They Just Learned

MANDATORY

exit 1

Ask them:

“What do you think will happen?”

Then run again.

❌ Result

• Build turns RED
  


• Jenkins stops


• No further steps run

Why?

• 
  exit 1 = failure


• Jenkins trusts exit codes


• This is how bad code blocks deployments

“Jenkins is stupid but honest.

If a command fails, Jenkins stops everything.”

That’s real DevOps.