Bash Tokenization Errors on Jenkins JNLP Slave

Why might the below bash commands give me an error on a Jenkins JNLP slave in Kubernetes cluster? Each work on a local machine.

Error: Syntax error: redirection unexpected

IFS='/' read -r -a branch <<< "${1}"

Error: Syntax error: "(" unexpected (expecting "}"):

IFS='/'
branch=($1)

Environment Details

• JNLP Slave is using Dockerhub jenkins/jnlp-slave:latest

• Slave being ran with kubernetes plugin

• Jenkins v2.156 on master.

• Command is from a sourced function in another script. (e.g. . "/script.bash")

I cannot say this is a the best answer so I do hope someone can provide a better clarification.

It seems the default shell for sh() in Jenkins is Bourne. By updating the sh() with the correct shell this allows the below usage:

sh'''#!/bin/bash
    IFS='/'
    branch=($1)
    # Use it.
'''

This doesn't resolve the the redirection error. Also I would think by updating the default shell in the image with chsh -s /bin/bash I wouldn't need to set it but I still do.

StackExchange DevOps Q#5990, answer score: 1