Date: Sun, 9 Sep 2001 22:53:16 +0200 From: Neil Blakey-Milner <nbm@mithrandr.moria.org> To: Ulf Zimmermann <ulf@Alameda.net> Cc: Alfred Perlstein <bright@mu.org>, hackers@FreeBSD.org Subject: Re: Question about what programs to use in /etc/rc* Message-ID: <20010909225316.A76366@mithrandr.moria.org> In-Reply-To: <20010909133800.C1500@seven.alameda.net>; from ulf@Alameda.net on Sun, Sep 09, 2001 at 01:38:00PM -0700 References: <20010909024721.B1500@seven.alameda.net> <20010909131152.L2965@elvis.mu.org> <20010909133800.C1500@seven.alameda.net>
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On Sun 2001-09-09 (13:38), Ulf Zimmermann wrote:
> On Sun, Sep 09, 2001 at 01:11:52PM -0500, Alfred Perlstein wrote:
> > * Ulf Zimmermann <ulf@Alameda.net> [010909 04:47] wrote:
> > > Hello everyone.
> > >
> > > I am looking at some PRs and I am trying to come up with a solution to
> > > submit a patch. I know how to use expr to test as tring in sh inside
> > > of a /etc/rc* script, but what method would people recommend to remove
> > > part of the string after expr confirmed that something is part of it ?
> > >
> > > These are some examples strings:
> > >
> > > "dhcp"
> > > "dhcp media 10baseTX"
> > > "media 10baseTX dhcp mediaopt half-duplex"
> > >
> > > The following code will get me inside a if condition:
> > >
> > > if [ `expr "${ifconfig_args}" : '.*[Dd][Hh][Cc][Pp].*'` -ne 0 ]; then
> > >
> > > ....
> > >
> > > fi
> > >
> > > What I would like to do inside the if .. fi is to remove "[Dd][Hh][Cc][Pp]"
> > > from the string so that the rest of the options can be used to call ifconfig.
> > > Otherwise the if .. fi will test if the string is then empty or just white
> > > spaces and if so it will not do anything but set ${dhcp_interfaces}. If its
> > > not empty it will call ifconfig with the extra options to set the interface.
> > >
> > > Awk/sed comes to mind but those are in /usr/bin and I am trying to avoid
> > > that.
> > >
> > > Any suggestions from the more experienced hackers ?
> >
> > sed? :)
> >
> > sed 's/[Dd][Hh][Cc][Pp]//g'
> >
> > -Alfred
>
> sed is in /usr/bin and so its not a too good idea to use it in a /etc/rc
> script. There is sed also in /stand, can that be used ?
Nope, you can't. However, you might be able to do it all within sh, by
using case and "Parameter Expansion" (see the section in the sh man
page).
Try this:
case ${ifconfig_args} in
*[Dd][Hh][Cc][Pp]*)
# do stuff with whatever
$ifconfig_args=${ifconfig_args%dhcp}
;;
esac
This probably won't work, since I've not tested it. Casedness is
irritating too - dd.sh would advocate converting it all to lowercase
with ``dd conv=lcase''. ;)
Neil
--
Neil Blakey-Milner
nbm@mithrandr.moria.org
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