From: Sunder Iyengar (Sunder.Iyengar@VERITAS.COM)
Date: Mon Dec 08 2003 - 18:53:46 EST
Simon,
To do what you want, just add two patterns:
awk '!/^ *\* */ {sub(....); print}
/^ *\* */ {print}' input-file
So, the substitution will only be done, where applicable, on lines that are
not commented out.
Comment lines are printed unchanged by the second pattern and action.
Sunder.
-----Original Message-----
From: Green, Simon [mailto:Simon.Green@EU.ALTRIA.COM]
Sent: Monday, 8 December 2003 8:09 PM
To: aix-l@Princeton.EDU
Subject: Re: Scripting: awk reg. exp.
I'd tried something similar earlier; with it I can exclude commented out
lines. Unfortunately, I want them to appear - unchanged - in the output
and instead they get dropped entirely.
Any other suggestions?
Simon Green
Senior Technical Analyst
Server Management (UNIX Services)
Altria ITSC Europe Ltd
Tel: +44 1242 284318
Fax: +44 1242 284510
> -----Original Message-----
> From: Sunder Iyengar [mailto:Sunder.Iyengar@VERITAS.COM]
> Sent: 05 December 2003 23:32
> To: aix-l@Princeton.EDU
> Subject: Re: Scripting: awk reg. exp.
>
>
> Since you are not interested in lines that are commented out with a *,
> try this as a pattern matching string to select only relevant lines:
>
> awk '!/^ *\* */ {sub(....) etc.}'
>
> This should not select any lines that have zero or more spaces
> followed by a *, followed by zero or more spaces, at the beginning of
> the line.
>
<SNIP>
> >>
> >> Hi!
> >> I'm trying to write a little script to automate some changes to
> >> /etc/qconfig: changing certain host names. I've decided to use awk
> >> even though (or perhaps "because") I'm not very familiar with it.
> >>
> >> So far, I've come up with:
> >> {sub(/host = old_name/,"host = new_name");print}
> >> ...and that works fine, except that it will also make changes to
> >> entries which have been commented out, which I would
> prefer to avoid.
> >>
> >> Is there some way of constructing the command so that it does not
> >> select those lines which have been commented out? Remember:
> >> /etc/qconfig uses an asterisk as a comment-character, which is damn
> >> stupid!
>
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