Simply execute this code in Groovy script :

node('MYNODE')

{ bat ''echo ON ''' } And it will loop infinitely (all I did is deleted a ' after the word bat by accident). Had to reboot server to end the task. Here is the output: Started by user anonymous ERROR: failed to start build org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed: WorkflowScript: 13: expecting ''', found '<EOF>' @ line 13, column 2. }

^

1 error

at org.codehaus.groovy.control.ErrorCollector.failIfErrors(ErrorCollector.java:302)
at org.codehaus.groovy.control.ErrorCollector.addFatalError(ErrorCollector.java:149)
at org.codehaus.groovy.control.ErrorCollector.addError(ErrorCollector.java:119)
at org.codehaus.groovy.control.ErrorCollector.addError(ErrorCollector.java:131)
at org.codehaus.groovy.control.SourceUnit.addError(SourceUnit.java:359)
at org.codehaus.groovy.antlr.AntlrParserPlugin.transformCSTIntoAST(AntlrParserPlugin.java:137)
at org.codehaus.groovy.antlr.AntlrParserPlugin.parseCST(AntlrParserPlugin.java:108)
at org.codehaus.groovy.control.SourceUnit.parse(SourceUnit.java:236)
at org.codehaus.groovy.control.CompilationUnit$1.call(CompilationUnit.java:161)
at org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:846)
at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:550)
at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:526)
at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:503)
at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:302)
at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:281)
at groovy.lang.GroovyShell.parseClass(GroovyShell.java:731)
at groovy.lang.GroovyShell.parse(GroovyShell.java:743)
at org.jenkinsci.plugins.workflow.cps.CpsGroovyShell.reparse(CpsGroovyShell.java:100)
at org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.parseScript(CpsFlowExecution.java:356)
at org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.start(CpsFlowExecution.java:323)
at org.jenkinsci.plugins.workflow.job.WorkflowRun.run(WorkflowRun.java:188)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:374)