Is it possible to capture the stdout from the sh DSL command in the pipeline

Try this:

def get_git_sha(git_dir='') {
    dir(git_dir) {
        return sh(returnStdout: true, script: 'git rev-parse HEAD').trim()
    }
}

node(BUILD_NODE) {
    ...
    repo_SHA = get_git_sha('src/FooBar.git')
    echo repo_SHA
    ...
}

Tested on:

• Jenkins ver. 2.19.1
• Pipeline 2.4

Now, the sh step supports returning stdout by supplying the parameter returnStdout.

// These should all be performed at the point where you've
// checked out your sources on the slave. A 'git' executable
// must be available.
// Most typical, if you're not cloning into a sub directory
gitCommit = sh(returnStdout: true, script: 'git rev-parse HEAD').trim()
// short SHA, possibly better for chat notifications, etc.
shortCommit = gitCommit.take(6)

See this example.

Note: The linked Jenkins issue has since been solved.

As mention in JENKINS-26133 it was not possible to get shell output as a variable. As a workaround suggested using of writ-read from temporary file. So, your example would have looked like:

sh "echo foo > result";
def output=readFile('result').trim()
echo "output=$output";

You can try to use as well this functions to capture StdErr StdOut and return code.

def runShell(String command){
    def responseCode = sh returnStatus: true, script: "${command} &> tmp.txt" 
    def output =  readFile(file: "tmp.txt")

    if (responseCode != 0){
      println "[ERROR] ${output}"
      throw new Exception("${output}")
    }else{
      return "${output}"
    }
}

Notice:

&>name means 1>name 2>name -- redirect stdout and stderr to the file name