docs: private static void writePid(String file, boolean ignorePidFile) {
        File pidFile = new File(file);
        if(pidFile.exists()) {
          Long oldPid = getPid(pidFile);
          if(oldPid==null) {
            pidFile.delete();
          } else {
            log.warn("\n\t==================================\n\tThe OpenTSDB PID file [" + file + "] already exists for PID [" + oldPid + "]. \n\tOpenTSDB might already be running.\n\t==================================\n");
            if(!ignorePidFile) {
              log.warn("Exiting due to existing pid file. Start with option --ignore-existing-pid to overwrite"); 
              System.exit(-1);
            } else {
              log.warn("Deleting existing pid file [" + file + "]");
              pidFile.delete();
            }
          }
        }
        pidFile.deleteOnExit();
        File pidDir = pidFile.getParentFile();
        FileOutputStream fos = null;
        try {
          if(!pidDir.exists()) {
            if(!pidDir.mkdirs()) {
              throw new Exception("Failed to create PID directory [" + file + "]");
            }
          }     
          fos = new FileOutputStream(pidFile);      
          String PID = ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
          fos.write(String.format("%s%s", PID, EOL).getBytes());
          fos.flush();
          fos.close();
          fos = null;
          log.info("PID [" + PID + "] written to pid file [" + file + "]");
        } catch (Exception ex) {
          log.error("Failed to write PID file to [" + file + "]", ex);
          throw new IllegalArgumentException("Failed to write PID file to [" + file + "]", ex);
        } finally {
          if(fos!=null) try { fos.close(); } catch (Exception ex) { /* No Op */ }
        }
      }