With the file open, you can assign its content to a variable
output with
input.readlines() and then print it as you
like. All of this can happen without knowing the file's descriptor.
But what if you want to handle more advanced tasks like getting the
status of the file or taking only the first 1024 bytes? For these you
need the file descriptor, abbreviated
fd. To get it, simply
run the
fileno() method of the file handle:
input.fileno()
In my shell session, Python returned '3'. If you open another file
and follow the same procedure without doing anything else in the
terminal, you will get '4'.
Knowing the file descriptor, we can resolve the first of the
aforementioned problems by calling
fstat():
>>> os.fstat(3)
(33188, 5225L, 11L, 1, 1000, 1000, 5834L, 1209359646, 1209359726, 1209359726)
This returns, among other things, the file's group ID, user ID, size,
inode, and sundry other bits about its status on the system. If
you are on a Unix variant, You can get even more information about the
file by running
os.fstatvfs(3).
