shell scripting question (mdconfig device choosing)

Luke Bakken luke.bakken at gmail.com
Wed Jan 25 07:17:46 PST 2006


> > > Yeah, but I am looking for "0" ... 8,9,11,14 are all in use ... but 0-7
> > > are not.  I want to:
> > >
> > > "starting with zero, find the lowest number that is NOT in this list"
> > >
> > > (where "this list" is the output of mdconfig -l, which shows which md
> > > devices are currently in use)
> >
> > Running mdconfig -l I don't get any output, however this works, it'll
> > find the first unused number up to 25 in that list.
> >
> > echo '8 9 11 14' | perl -ane'@h{@F}=(1)x at F;for(0..25){if(not defined
> > $h{$_}){print qq($_\n);exit}}'
> >
> > If you can give me the exact output of mdconfig -l, I can modify this for you.
>
>
> Thank you very much - you got no output because you have no md devices in
> use.  I have a few in use and this is the output I get:
>
> # mdconfig -l
> md3 md2 md1 md0
>
> But I could just as easily get:
>
> # mdconfig -l
> md9 md8 md5 md3
>
> Hmm...I just saw that that line is in perl, and I do not have perl
> installed on any of my 6.0 machines ... I am not sure I want to install it
> just for this one shell script :(

Whoops, I forgot that perl isn't in the base any more. What scripting
languages do you have? If you only have sh, I'll work on that, but it
won't be a one-liner most likely. Or a C program.


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