Parsing LISTENER.ORA with awk and sed

Happy Thanksgiving to everyone in the US! And happy belated thanksgiving to everyone in Canada since you celebrated back at the beginning of October. :)

I’ve been doing a lot of scripting work lately. Although I can’t write about everything I’m doing, I would like to post a pattern that I thought could be useful to other folks. I needed to update some properties in the LISTENER.ORA file from a shell script. The problem is that basically you have to clobber it or properly parse it! Even though I initialized this listener file myself, there is always the possibility that a DBA could manually edit it – so I didn’t want to clobber the contents. That means that I had to parse it.

So how do you parse a listener file from a shell script? I came up with a nifty way to tokenize and parse the file through a simple awk script combined with sed – and it seemed rather useful so I refactored it a few times to apply to more general use cases. I think someone else could use something like this too so I’m posting it – do me a favor and keep the reference to ardentperf in there if you copy the code.

There’s two functions that are basically the same pattern: the first will read an attribute and the second will set one. I’ve included some examples at the bottom of the post. I’ve tried to make the awk code portable but so far I’ve only tested it with gawk and mawk on a few flavors of Linux.
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