[augeas-devel] Path and increasing identifiers

[Raphaël Pinson]

On Wed, Dec 16, 2009 at 5:48 PM, David Lutterkort <lutter at redhat.com> wrote:
> On Wed, 2009-12-16 at 15:39 +0100, Raphaël Pinson wrote:
>> On Wed, Dec 16, 2009 at 3:28 PM, Tim Stoop <tim.stoop at gmail.com> wrote:
>> > Hi all,
>> >
>> > I'm trying to knit some of our puppet recipes together with Augeas,
>> > because I think the Augeas way of working is much nicer than sourcing
>> > files. However, I'm running into one thing I can't seem to solve: Take
>> > the /etc/hosts file, every entry has a unique identifier (like
>> > /files/etc/hosts/1/), how do I determine which one is the highest, so
>> > I can automatically do something like last()+1 for a new IP address?
>> >
>>
>> last()+1 is exactly it :-)
>> e.g. augtool print '/files/etc/hosts/*[last()]'
>>
>>
>> And your can use last()+1 in your insert command.
>
> The trick with adding by using last()+1 only works if you know the label
> of the new node, like for adding an alias:
>
>        set /files/etc/hosts/1/alias[last()+1] myhost.example.com
>
> but not when you don't know the label, i.e.
>
>        set /files/etc/hosts/*[last()+1]/ipaddr 192.168.0.1
>
> will fail, since Augeas has no clue what to call the tree node it has to
> create for the *[last()+1] bit in the path.
>

Ah, thanks for the clarification David, that makes perfect sense :-)



> David
>
>
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