Groovy executing shell commands

println "ls".execute().text

def x = shellDo("ls /tmp/NoFile")
 println "out: ${x.out} err:${x.err}"

def sout = new StringBuffer(), serr = new StringBuffer()
def proc = 'ls /badDir'.execute()
proc.consumeProcessOutput(sout, serr)
proc.waitForOrKill(1000)
println "out> $sout err> $serr"

def proc = "ls".execute()
def b = new StringBuffer()
proc.consumeProcessErrorStream(b)

println proc.text
println b.toString()