From: Dave Thomas <dave@...>
Date: 2008-08-14T05:50:41+09:00
Subject: Re: Potentially issues with "system" command (Nuby)


On Aug 13, 2008, at 3:32 PM, Thomas Luedeke wrote:

> I'm pretty new at this - what is the command to do so?


dave[ATCOCOA/Book 15:47:45] ri Process::Status
------------------------------------------------- Class: Process::Status
      Process::Status encapsulates the information on the status of a
      running or terminated system process. The built-in variable $? is
      either nil or a Process::Status object.

         fork { exit 99 }   #=> 26557
         Process.wait       #=> 26557
         $?.class           #=> Process::Status
         $?.to_i            #=> 25344
         $? >> 8            #=> 99
         $?.stopped?        #=> false
         $?.exited?         #=> true
         $?.exitstatus      #=> 99

      Posix systems record information on processes using a 16-bit
      integer. The lower bits record the process status (stopped,
      exited, signaled) and the upper bits possibly contain additional
      information (for example the program's return code in the case of
      exited processes). Pre Ruby 1.8, these bits were exposed directly
      to the Ruby program. Ruby now encapsulates these in a
      Process::Status object. To maximize compatibility, however, these
      objects retain a bit-oriented interface. In the descriptions that
      follow, when we talk about the integer value of stat, we're
      referring to this 16 bit value.


You can just use

   p $?

to get information. If it was signaled (perhaps because a process  
limit was exceeded) you can find the cause.

Dave