title: How to execute shell command in Groovy and get the return code $?
body: <p>I can't get the return code (not the output or error) from executing a shell script within Groovy.</p>
  
  <p>For all what I tried, it either ask me to escape or just print the $? instead of give me 1 or 0.</p>
  
  <p>groovy: 75: illegal string body character after dollar sign;
     solution: either escape a literal dollar sign "\$5" or bracket the value expression "${5}" @ line 75, column 24.</p>
  
  <p>Below are solutions I tried, all don't work.</p>
  
  <pre><code>println "../src/check_job_log.s ${it}.log".execute().text
  println "Check log ${it}.log completed"
  
  //assert ("echo \$?".execute().text == "1")
  //output = """echo $?""".execute().text
  println(['echo', '$?'].execute().text)
  
  // below is code for  @that other guy
  //def process = "echo hello world".execute()
  def process = "../src/check_job_log.s ${it}.log".execute()
  print "Output: " + process.text
  print "Exit code: " + process.exitValue()
  
  Output: Exit code: 01
  </code></pre>