""""Script demonstrating how subprocess.Popen() does work with a file
 object that has been seek'ed only once.
"""

import subprocess

# Open a file (and call seek on it)
rawfile = file('hello.txt', 'rb')
rawfile.readline()
rawfile.seek(0) # Seek back to the start of the file, changing the file pointer

# Run cat to print the contents of the file
program_arguments = ["cat"]
process_object = subprocess.Popen(program_arguments, stdin=rawfile, \
        stdout=subprocess.PIPE, stderr=subprocess.PIPE)

print "File contents from Popen() call to cat:"
print process_object.stdout.read()

process_object.wait()