What does "from ... import ..." mean in simple bonehead terms?
<pre><code>from sys import argv
from os.path import exists

script, from_file, to_file = argv

print "Copying from %s to %s" % (from_file, to_file)

# we could two on one line too, how?
input = open(from_file)
indata = input.read()

print "The input file is %d bytes long" % len(indata)
print "Does the output file exist? %r" % exists(to_file)
print "Ready, hit return to continue, CTRL-C to abort."

raw_input()

output = open(to_file, 'w')
output.write(indata)

print "Alright, all done."

output.close()
input.close()
</code></pre>

<p>On the first two lines I have some idea of what is going on, but want to make sure I fully understand it, as this seems like it might be important.</p>
