[Tutor] updating Unix config file

[Matt Herzog]

On Mon, Oct 19, 2009 at 08:07:47PM +0100, Alan Gauld wrote:
> 
> "Matt Herzog" <msh at blisses.org> wrote
> 
> >remembered that strings are immutable. 
> >So how was I able to change the strings for my dotted quad? 
> 
> You didn't.
> 
> >LASTKNOWN = '173.48.204.168'
> >   lns = cf.readlines()
> >   lns = "".join(lns)
> >   lns = re.sub(LASTKNOWN, CURRENT, lns)
> 
> I assume this is the line in question?
> sub() returns a new string containing the substitutions.
> 
> HTH,

Yes! It sure does help. I just discovered that my script does not exit if the CURRENT IP is the same as the LASTKNOWN IP. 

------------------------------ snip --------------------------------------
CURRENT = socket.getaddrinfo(socket.gethostname(), None)[0][4][0]
------------------------------ snip --------------------------------------
Turns out the above is an unreliable way to get the IP of the interface since the machine the above is running on does not have a proper hostname and is a dhcp client on a broadband network. 

Anyway, I'd like a hint as to how I could convert this:

ifcfg_lines = os.popen("/sbin/ifconfig fxp0").readlines()
x = string.split(ifcfg_lines[3])[1]

to the subprocess module. The os module is going away, right?


> 
> 
> -- 
> Alan Gauld
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/
> 
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