It says I am using Cog 4.3.3 I also used the code of John pfersich
p :=(PipeableOSProcess waitForCommand: 'ls') . p output. and it still returns an empty string while the process is "a PipeableOSProcess on an ExternalUnixOSProcess with pid 769 on /bin/sh (complete, normal termination with status 0)" I tried debugging but it froze the image with a UndefinedObject(Object)>>doesNotUnderstand: #stepToCallee this happened inside BlockClosure >> newProcess at Processor terminateActive When I execute the command it works fine because I can see the output in the terminal. On Fri, Nov 6, 2015 at 5:23 AM David T. Lewis <le...@mail.msen.com> wrote: > On Fri, Nov 06, 2015 at 12:41:58AM +0000, Dimitris Chloupis wrote: > > hello David and thank you for your help and your detailed explanation. > > > > as I said I used > > > > p :=(PipeableOSProcess command: 'ls') . p output. > > > > and it just returns an empty string. > > The way this should work is that p (an instance of PipeableOSProcess) > should > answer its output up to EOF (end of file) on the stdout from the process. > > Can you please try stepping through this slowly in a debugger, and see if > it works? Or put "(Delay forSeconds: 1)" right before you do "p output"? > I am guessing that there may be something about the OSProcessPlugin in your > VM that is causing EOF detection to fail, such that you just get an empty > string as output. > > I do not have a Mac to test, so I am only guessing. It might also be a > bug in the OSProcess plugin, I'm not sure. > > Just to help me identify what your are running, could you please evaluate > "OSProcess accessor osppModuleVersionString" and let me know what it says? > The current version would be '4.6.1' but other versions may be in > circulation, > and that could affect EOF detection. > > Thanks, > Dave > > > > > > Are there other ways to return the output of the terminal ? > > > > On Fri, Nov 6, 2015 at 1:57 AM David T. Lewis <le...@mail.msen.com> > wrote: > > > > > On Thu, Nov 05, 2015 at 09:50:29PM +0000, Dimitris Chloupis wrote: > > > > So I try to understand how OSProcess work exactly to find why > filetree > > > > seems not able to use it and generating the error I already reported > > > > earlier. > > > > > > > > Using something simple like > > > > > > > > OSProcess command:'pwd' > > > > > > > > works great , I have the terminal open and I can see the correct > return > > > > value of the command in my terminal but for some reason I can find no > > > such > > > > info when I inspect the above example. So how exactly OSProcess > returns > > > the > > > > output of the terminal ? Is there an instance variable of some sort ? > > > > Because I tried to inspect it deeply and I found nothing . Can you > help > > > me > > > > understand how OSProcess work ? Because If I do understand it then I > can > > > > find what the problem is . > > > > > > Hi Dimitris, > > > > > > The OSProcess and CommandShell packages provide a variety of ways to > > > create and interact with operating system processes. In the case of > > > "OSProcess command: 'pwd'" it is starting a new unix shell (/bin/sh, > which > > > on most systems is the Bash shell). Once it starts the shell, it asks > > > the shell to evaluate the 'pwd' command. In this case, you would see > the > > > output of that 'pwd' command appearing in the terminal window for your > > > Pharo VM process. > > > > > > If you inspect the result of this, you should see an instance of > > > ExternalUnixOSProcess. This is a proxy that represents the operating > > > system process that was used to run /bin/sh. It should look something > like > > > this: > > > > > > an ExternalUnixOSProcess with pid 10703 on /bin/sh (complete, normal > > > termination with status 0) > > > > > > The exitStatus instance variable of the ExternaUnixProcess should be 0 > in > > > this example, which means only that the shell ran successfully (It > does not > > > tell you exit status of the 'pwd' command in this case, although there > are > > > other ways to do that). > > > > > > There are other classes, especially PipeableOSProcess and CommandShell, > > > that support higher level control of OS processes, with direct > connection > > > of the stdin/stdout/stderr streams to your Smalltalk image. I expect > that > > > filetree would be using these higher level abstractions. > > > > > > I don't know if this helps with your problem but maybe it gives you > some > > > ideas. > > > > > > Dave > > > > > > > > > > >
