slight followup ... I have made some progress; for now I'm using subprocess.communicate to read the output from the first subprocess, then writing it into the secodn subprocess. This way I at least get to see what is happening ...
The reason 'we' weren't seeing any output from the second call (the 'xargs') is that as mentioned I had simplified this. The actual shell command was more like (in python-speak): "xargs -I {} sh -c \"test -f %s/{} && md5sum %s/{}\"" % (mydir, mydir) ie. I am running md5sum on each tar-file entry which passes the 'is this a file' test. My next problem; how to translate the command-string clause "test -f %s/{} && md5sum %s/{}" # ... into s parameter to subprocss.Popen(). I think it's the command chaining '&&' which is tripping me up... Cheers J^n -- http://mail.python.org/mailman/listinfo/python-list