gistfile1.txt

                                          def check_status                                                                                                                                     
~                              |+           if File.exists?(PID_FILE)                                                                                                                          
~                              |+             pid = File.read(PID_FILE).to_i                                                                                                                   
~                              |+             check_pid_status(pid) if pid > 0                                                                                                                 
~                              |+             File.delete(PID_FILE)                                                                                                                            
~                              |+           end                                                                                                                                                
~                              |+         end                                                                                                                                                  
~                              |+                                                                                                                                                              
~                              |+         def check_pid_status(pid)                                                                                                                            
~                              |+           Process.kill(0, pid)                                                                                                                               
~                              |+           puts "Process(#{pid}) is already running."                                                                                                         
~                              |+           exit(1)                                                                                                                                            
~                              |+         rescue Errno::ESERCH #do nothing, and continue with the script                                                                                       
~                              |+         rescue Errno::EPERM                                                                                                                                  
~                              |+           puts "Process with pid=#{pid} is already running but is owned by a different user"                                                                 
~                              |+           exit(1)                                                                                                                                            
~                              |+         end