call shell commands; synchronous return

Hi,

The method I've been using for submitting shell commands is asynchronous...

For example:-
     shellCmd := '<long running shell command here>'.
     pipe := FileStream popen: shellCmd dir: FileStream read.

pipe returns after about a second no matter how long the shell command
takes to complete.

Is there a way to call shell commands in a synchronous fashion?

Thanks
Stephen


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Stephen wrote:
Smalltalk system: 'abc'

Paolo


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Paolo Bonzini wrote:
> Smalltalk system: 'abc'
>
> Paolo
>

Thanks

shellOut := Smalltalk system: 'sleep 5 && ls -l /etc && sleep 10'.
Transcript showCr: shellOut printString.

That worked a treat.

Is there anything one should be aware of when choosing between the two
ways of calling shell commands? The system: call above appeals since it
is synchronous and provides the shell output, but just wondering if
there is a situation when it is better to use the "Filestream popen:
dir" command.

And is there a way to get access to the standard error stream?

Thank you again

Stephen



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Then found that Smalltalk system: returns an integer rather than the
shell output.

So here is what I wanted to do:

" Part 1: shut down running VMWare VMs"
shellCmd := '/usr/bin/vmrun list'.
pipe := FileStream popen: shellCmd dir: FileStream read.
pipe linesDo: [: vmName |
    shellCmd2 := '/usr/bin/vmware-cmd %1 stop' bindWith: vmName.
    pipe2 := FileStream popen: shellCmd2 dir: FileStream read.     ]

Hence the need for a synchronous call so that the script waits until
each machine is shut down.


Thanks
Stephen


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Do you need the output of the second command?  If no, obviously you can
use popen for the outer loop and system for the inner loop.  Otherwise,
closing a pipe or sending it #contents will also wait for the process to
end.

Paolo


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