[ILUG] grep or awk

[Chris Higgins]

We're talking about the contents of the wtmp/utmp files, as interpreted by
the command 'who'

If you upgrade your version of who, and the formatting changes slightly,
you run the risk of breaking your scripts (in strange and wonderful ways).

Would it not make more sense to query the files directly so that 
you can be sure that the information is more reliable than grep'ing
from 'who'

Chris (just my e0.02) - (see: man utmp)

> Fergal Daly wrote:
> > sed 's/.*(\(.*\)).*\|.*/\1/'
> > 
> > will turn lines that don't have a matching pair of brackets into blanks,
> > 
> > > >     xxxxxxx     ttyqb       Sep 10 11:33
> > > > (xxx.xxx.xxx.xxx)
> 
> I think 
> sed -e 's/^[^(]*(\([^)]*\)).*$/\1/'
> is slightly better, in that it will pick up the first matching pair of
> brackets, rather than (on this line, say) printing (for example) "on
> this line, say) printing (for example" rather than "on this line, say" -
> but that's a matter of choice, if you're guaranteed that you'll only
> have one pair of brackets.
> 
> Cheers,
> Dave 
> 
> -- 
> David Neary,               E-Mail dave.neary at palamon.ie
> Palamon Technologies Ltd.  Phone +353-1-634-5059
> 
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-- 
** Chris Higgins                         e: chris.higgins at horizon.ie **
** Technical Business Development        tel: +353-1-6204916            **
** Horizon Technology Group              fax: +353-1-6204949            **