Shell steps (sh, bat) in Jenkins - Commands & Configuration

Introduction

Jenkins can run shell commands directly in its pipelines. This lets you automate tasks like building, testing, or deploying software by running simple scripts inside your pipeline.

When you want to run Linux shell commands in a Jenkins pipeline on a Linux agent.

When you need to execute Windows batch commands in a Jenkins pipeline on a Windows agent.

When you want to automate running scripts without creating separate script files.

When you want to quickly test commands inside your Jenkins pipeline.

When you need to run commands that prepare your build environment or clean up after builds.

Commands

This Jenkins pipeline runs a shell command on any available agent. The 'sh' step runs the Linux shell command to print a message.

Terminal

pipeline {
    agent any
    stages {
        stage('Run Shell') {
            steps {
                sh 'echo Hello from Linux shell'
            }
        }
    }
}

Expected Output

[Pipeline] {

[Pipeline] stage

[Pipeline] { (Run Shell)

[Pipeline] sh

+ echo Hello from Linux shell

Hello from Linux shell

[Pipeline] }

[Pipeline] // stage

[Pipeline] }

[Pipeline] // pipeline

This Jenkins pipeline runs a Windows batch command on any available agent. The 'bat' step runs the Windows batch command to print a message.

Terminal

pipeline {
    agent any
    stages {
        stage('Run Batch') {
            steps {
                bat 'echo Hello from Windows batch'
            }
        }
    }
}

Expected Output

[Pipeline] {

[Pipeline] stage

[Pipeline] { (Run Batch)

[Pipeline] bat

+ echo Hello from Windows batch

Hello from Windows batch

[Pipeline] }

[Pipeline] // stage

[Pipeline] }

[Pipeline] // pipeline

Key Concept

If you remember nothing else, remember: use 'sh' to run Linux shell commands and 'bat' to run Windows batch commands inside Jenkins pipelines.

Common Mistakes

Using 'sh' step on a Windows agent or 'bat' step on a Linux agent.

The command will fail because the shell environment does not exist on that agent type.

Use 'sh' only on Linux agents and 'bat' only on Windows agents.

Not quoting the command string inside 'sh' or 'bat' steps.

Jenkins may misinterpret the command or fail to run it properly.

Always put the command inside single quotes to ensure it runs as intended.

Summary

Use 'sh' step to run Linux shell commands in Jenkins pipelines.

Use 'bat' step to run Windows batch commands in Jenkins pipelines.

Always match the step to the agent OS to avoid errors.

Practice

1. In Jenkins pipelines, which shell step should you use to run a command on a Linux agent?

easy

A. bat

B. sh

C. cmd

D. powershell

Solution

1. Step 1: Understand Jenkins shell steps

   Jenkins uses sh to run shell commands on Linux/macOS agents.

2. Step 2: Identify the correct shell for Linux

   Since Linux uses bash or sh shells, sh is the correct step.

3. Final Answer:

   sh -> Option B

4. Quick Check:

   Linux shell step = sh [OK]

Hint: Use sh for Linux/macOS, bat for Windows agents [OK]

Common Mistakes:

• Using bat on Linux agents
• Confusing cmd with sh
• Using powershell on non-Windows agents

2. Which of the following is the correct syntax to run a Windows batch command in a Jenkins pipeline?

easy

A. sh 'dir'

B. cmd 'dir'

C. powershell 'dir'

D. bat 'dir'

Solution

1. Step 1: Identify Windows shell step in Jenkins

   Jenkins uses bat to run Windows batch commands.

2. Step 2: Match syntax for batch command

   The correct syntax is bat 'command', so bat 'dir' is correct.

3. Final Answer:

   bat 'dir' -> Option D

4. Quick Check:

   Windows batch command = bat [OK]

Hint: Use bat for Windows commands in Jenkins pipelines [OK]

Common Mistakes:

• Using sh for Windows commands
• Using cmd which is not a Jenkins step
• Using powershell without proper syntax

3. What will be the output of this Jenkins pipeline snippet on a Linux agent?

sh 'echo Hello Jenkins'

medium

A. Hello Jenkins

B. sh: command not found

C. echo Hello Jenkins

D. Syntax error

Solution

1. Step 1: Understand the sh step execution

   The sh step runs the command inside quotes on the Linux shell.

2. Step 2: Predict command output

   The command echo Hello Jenkins prints the text 'Hello Jenkins' to the console.

3. Final Answer:

   Hello Jenkins -> Option A

4. Quick Check:

   sh echo outputs text [OK]

Hint: sh runs commands and prints their output on Linux [OK]

Common Mistakes:

• Expecting the command itself as output
• Confusing syntax error with correct command
• Assuming sh step fails on Linux

4. You wrote this Jenkins pipeline step:

bat 'echo Hello from Linux'

But it runs on a Linux agent and fails. What is the problem?

medium

A. bat is for Windows, not Linux

B. echo command is invalid

C. Missing quotes around command

D. Pipeline syntax error

Solution

1. Step 1: Identify shell step and agent OS mismatch

   The bat step runs Windows batch commands, but the agent is Linux.

2. Step 2: Understand why failure occurs

   Linux agents do not support bat, so the step fails.

3. Final Answer:

   bat is for Windows, not Linux -> Option A

4. Quick Check:

   bat step on Linux = failure [OK]

Hint: Match shell step to agent OS: bat=Windows, sh=Linux [OK]

Common Mistakes:

• Thinking echo is invalid on Linux
• Assuming quotes cause error
• Blaming pipeline syntax instead of shell step

5. You want to write a Jenkins pipeline that runs a shell command on both Windows and Linux agents. Which approach is best?

hard

A. Use sh step for all agents

B. Use bat step for all agents

C. Use sh for Linux and bat for Windows with if condition

D. Use powershell step for all agents

Solution

1. Step 1: Recognize OS differences in shell steps

   Linux agents require sh, Windows agents require bat.

2. Step 2: Use conditional logic in pipeline

   Use an if condition to detect OS and run the correct shell step.

3. Final Answer:

   Use sh for Linux and bat for Windows with if condition -> Option C

4. Quick Check:

   Conditional shell steps match OS [OK]

Hint: Use if condition to select sh or bat by OS [OK]

Common Mistakes:

• Using one shell step for all OSes
• Ignoring agent OS detection
• Using powershell without Windows-only context