best way to copy a file [Q]

[Matthew Dixon Cowles]

In article <000201be8441$7965d4d0$6eba0ac8 at kuarajy.infosys.com.ar>, "Bruno
Mattarollo" <brunomadv at ciudad.com.ar> wrote:

> Hi!
> 
>         I need to copy a file (can be binary or ascii) from one path to 
> another. I
> have tryied to do:
>         line = fd.readline()
>         while line:
>                 fd2.write(line)
>                 line = fd.readline()
>         fd.close()
>         fd2.close()
> 
>         It only works for ascii files ... How can I do a 'copy' ...? I
need to 
> run
> this on NT ...:(  And I don't want to open a shell to do a copy from
> there... I also tryied fd.read() ... No success neither. I have looked
> unsuccesfully throughout the documentation and didn't find a 'filecopy'
> method. The files can range from 1KB to 600MB+ ...

Bruno,
You need to open the files in "binary" mode since Windows makes a
distinction between text and binary files. I understand that something
like

in=open("file","rb")
out=open("file2","wb")

should work. Also, you might want to reconsider using readline() for
binary files. If a large binary file happened not to contain \r\n,
readline() might try to grab an unreasonably large piece of the file:

>>> foo=open("/dev/zero")
>>> foo.readline()
Bus error

The function copyfile() in the standard module shutil would probably work
well for you. But now you know why <wink>.

Regards,
Matt