Shell steps (sh, bat) in Jenkins - Step-by-Step Execution

Process Flow - Shell steps (sh, bat)

Start Jenkins Pipeline

↓

Execute shell step

↓

Run command in shell

↓

Capture output and status

↓

Use output or handle errors

↓

Continue or stop pipeline

The Jenkins pipeline runs a shell step, executes the command, captures output and status, then continues or stops based on results.

Execution Sample

Jenkins

pipeline {
  agent any
  stages {
    stage('Shell Step') {
      steps {
        sh 'echo Hello Jenkins'
      }
    }
  }
}

This pipeline runs a shell command that prints 'Hello Jenkins' to the console.

Process Table

Step	Action	Command Executed	Output	Status
1	Start pipeline	-	-	Running
2	Enter stage 'Shell Step'	-	-	Running
3	Execute shell step	echo Hello Jenkins	Hello Jenkins	Success
4	Shell step completed	-	-	Success
5	Pipeline continues or ends	-	-	Success

💡 Shell command executed successfully, pipeline continues.

Status Tracker

Variable	Start	After Step 3	Final
output	null	Hello Jenkins	Hello Jenkins
status	null	Success	Success

Key Moments - 2 Insights

Why does the pipeline stop if the shell command fails?

Because Jenkins treats a non-zero exit code from the shell step as a failure, stopping the pipeline as shown in step 3 if status is not 'Success'.

How can I capture the output of the shell command for later use?

You can assign the output to a variable using 'def output = sh(script: "command", returnStdout: true).trim()' to use it later, unlike the simple 'sh' step shown in the table.

Visual Quiz - 3 Questions

Look at the execution table, what is the output after step 3?

A echo Hello Jenkins

B Success

C Hello Jenkins

D -

💡 Hint

Check the 'Output' column in row for step 3.

At which step does Jenkins run the shell command?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look at the 'Action' and 'Command Executed' columns to find when the command runs.

If the shell command returned an error, what would happen to the pipeline status at step 4?

A Status would be 'Success'

B Status would be 'Failure'

C Status would be 'Running'

D Status would be '-'

💡 Hint

Refer to the explanation in key moments about non-zero exit codes stopping the pipeline.

Concept Snapshot

Jenkins shell steps run commands in a shell environment.
Use 'sh' for Linux/macOS and 'bat' for Windows.
Commands run inside pipeline stages.
Output and status are captured.
Non-zero exit codes fail the pipeline.
Use 'returnStdout: true' to capture output.

Full Transcript

In Jenkins pipelines, shell steps like 'sh' run commands in a shell environment. The pipeline starts, enters a stage, executes the shell command, captures its output and status, then continues or stops based on success or failure. For example, running 'sh "echo Hello Jenkins"' prints 'Hello Jenkins' and returns success. If the command fails, Jenkins stops the pipeline. You can capture command output by using 'returnStdout: true' in the shell step. This visual trace shows each step from starting the pipeline to executing the shell command and handling the result.