newb Q

[Matthew Dixon Cowles]

In article <39794752.D54A50CD at mediaone.net>, Toy <gee308 at mediaone.net>
wrote:

> Thanks for showing me how to do that.  I tried to edit something, but it
> didn't work, I'll show you:
> 
> 
> def getMyAddr():
>   object = raw_input(Which device is connect to the internet(i.e. ppp0, eth0,
> ne3: ")
>   p=os.popen("/sbin/ifconfig",object)
> 
> Is it possible to do that?

It's possible to do something like that. The argument to os.popen (and
to os.system) needs to be a character string. So you need to build up
the string so that it looks just like what you'd type at the keyboard.
The string concatenation operator is +, so you'd do something like:

dev=raw_input("Device name? ")
p=os.popen("/sbin/ifconfig "+dev)

> Will it work with os.system?  What are the differences bewteen using
> os.popen and os.system?

os.system is similar to os.popen in that both execute a command of the
sort that you'd ordinarily type at a shell prompt. They're different in
that os.system just executes that command and if the command produces
any output, it's printed in your shell window, while os.popen (if you
accept its default) returns a file-like object that you can use to read
the output that the command produces and use it in your program.

> BTW, I only compared OpenBSD 2.7, Linux 2.2.15, and FreeBSD 4.0, but it seems
> if you do the string search  on ifconfig with find text on 1 line beginning
> with inet and ending with mask, It looks like you can get the IP from those 3
> machines.(of coure I still can't write some code to actually do it).

In situations like this, it's generally possible to find some mechanism
that works almost all of the time. It's also almost always the case
that eventually something that you were depending on will change and
you'll have to fix your code.

Regards,
Matt