On 26 Feb 2007 at 18:13, D. Bolliger wrote:
> Beginner am Montag, 26. Februar 2007 17:02:
> > On 26 Feb 2007 at 15:58, D. Bolliger wrote:
> > > Beginner am Montag, 26. Februar 2007 14:50:
>
> Hi
>
> > > > I am trying to parse some dhcp-lease files to extract the ip, mac and
> > > > hostname.
..snip
>
> > Thanx Dani,
> >
> > That's worked a treat. Just to complete the learning curve, where was
> > I going wrong?
>
> That should have been part of my first answer, sorry. I'll try and hope I
> don't mess with the test versions and the english language :-)
>
> Looking at the regex:
>
> It only matches MACs without a-c hex digits (and there's no 'scien' string in
> the data, but that's probably due to the altered hostnames, and I assume that
> the \d{3} in the IP matching part is intended.).
>
> In the script version with $/ = '':
>
> This reads all records at once, and this seems to be the reason why you used
> the /g modifier. But then, after matching the IP of the first lease, the
> first .* will skip all leases except the last one for the mac/host matching.
> So you (or I respectively) get a single wrong result with the IP of the
> first lease and mac/host of the last lease (after correcting the mac regex
> part).
> So you would have to alter the .* into the non-greedy .*? (to avoid
> skipping leases) and also append a .*? at the end of the regex to match what
> is "between the leases" [argh!] (to avoid only one match).
>
> But even if the regex is correct, and the ip/mac/host of every lease is
> matched, only the first 3 captured matches get stored into ($ip,$mac,$host),
> and the others are discarded (which would not be the case with
> @data=/....../g).
>
> When you tried with $/ = "}\n":
>
> I don't know neither how the regex looked like in this case, nor what went
> wrong then, so I can't say much.
>
> Other notes:
>
> The $_=~ is not necessary, because if the left side of =~ is missing, $_ is
> used by default.
>
> To read all leases, you could also do it like so to avoid the somehow
> misleading while loop:
> {
> local $/; # sets $/ to undef
> my $data=<FH>; # slurp entire file
> # ...match with /g modifier...
> }
>
> chomp is not necessary.
>
> Hope that covers the most important issues :-)
>
> Dani
Thanx Dani (and John) that's a very complete reply with a lot of
useful stuff to bear in mind.
There were a couple of errors that slipped in after I tried to
ofuscate my domain and ip range but I was missing a great deal.
Thanx again.
Dp.
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