I tried to use your code but I don't have either class in my 4.3 or 4.4 images. Do they require adding something?
On Mon, Jun 17, 2013 at 1:38 PM, David T. Lewis <le...@mail.msen.com> wrote: > On Mon, Jun 17, 2013 at 10:16:05AM -1000, OpenSlate ChalkDust wrote: > > On Wed, Jun 12, 2013 at 2:47 AM, David T. Lewis <le...@mail.msen.com> > wrote: > > > > > On Tue, Jun 11, 2013 at 10:34:47PM -0700, Sean P. DeNigris wrote: > > > > When using PipeableOSProcess as a shell, how can I get feedback on > the > > > status > > > > of the individual commands? > > > [snip] > > > PipeableOSProcess is designed to be part of CommandShell, so when you > use > > > it > > > directly (rather than using a CommandShell), you need to take care of > a few > > > details. The important things are to set the output pipe for > nonblocking > > > reads > > > (otherwise you will hang up your VM on a read), and to close pipes > when you > > > are done using them (otherwise you will "leak" file handles over time). > > > > > > Dave > > > > > > > > Could the example you gave be implemented using CommandShell? In what > > situations would I want to use PipeableOSProcess instead of CommandShell? > > Good question. CommandShell works at a higher level, and it manages the > annoying details of closing pipe handles and making sure that you do > not block the VM. In most cases, it is easier to use CommandShell rather > than operating directly on the lower level PipeableOSProcess. > > For example (to build on the earlier example), if you want to run the > Unix 'ls' command, and check its exit status to determine if a file was > not found, it is not necessary to use the lower level PipeableOSProcess. > You can do this instead: > > CommandShell new > if: 'cd .. ; ls aFile' > then: ['the ls command succeeded'] > else: ['the file was not found'] ==> 'the file was not found' > > Having said that, CommandShell is a simple simulation of a Unix shell, > and it is not a complete replacement for something like bash. There > are cases when you may need to use the features of a real Unix shell, > so working directly with a PipeableOSProcess connected to /usr/bin/bash > may be necessary in some cases. > > Dave > > _______________________________________________ > Beginners mailing list > Beginners@lists.squeakfoundation.org > http://lists.squeakfoundation.org/mailman/listinfo/beginners > -- Gary Dunn Open Slate Project http://openslate.org/
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