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From: afc@shibaya.lonestar.org (Augustine Cano)
Newsgroups: comp.unix.shell
Subject: sh loop variable and "double indirection"
Message-ID: <1991Jan27.044258.18779@shibaya.lonestar.org>
Date: 27 Jan 91 04:42:58 GMT
Organization: Multidisciplinary Designs Unlimited
Lines: 51

I am trying to specify (at run time) an upper limit for a loop in a shell
script.  In pseudo-code the ideal would be something like this:

read i
for 0 to i
do
...
done

The closest I've come to this is what follows:

echo "enter upper limit"
read limit
for i in 0 1 2 3 4 5 6 7 8 9
do
# some processing that involves $i goes here
if test $i -ge $limit-1 ; then	# NOTE: for i=3, I want iterations 0,1,2
  break
fi
done

Not very elegant since a limit of 10 iterations is hard-wired.  Can anybody
think of a more concise way to do this?  Using PERL is not an option, this
must be portable sh code.

The next problem is the thorny one.  Some shell variables having been
previously set up, say:

var0=REAL_VALUE0
var1=REAL_VALUE1
var2=REAL_VALUE2
var3=REAL_VALUE3
var4=REAL_VALUE4

I want to manipulate variable names inside the above loop such that
I could display the "REAL VALUEx" based on the current value of $i.

At the prompt, with the above variables initialized, echo $var0,
echo $var1, etc... yield the expected results.  When I put
echo $var$i in the loop, it doesn't work.  Other variations, such as
echo $"$var$i", etc... don't work either.  How can this be done?

How is it possible to make sh group $var and $i first and then get the
real value of the variable that results from combining the 2 strings?

Any help will be greatly appreciated!!!  I'll summarize e-mail responses.

Thanks in advance.
-- 
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