Re: Passing variables to and from custom programs

[Mike Stroyan]

On Sat, Feb 06, 2010 at 05:35:21PM -0800, DennisW wrote:
> On Feb 6, 5:37 pm, djackn <jack.nadel...@yahoo.com> wrote:
> >     Result = myIpExec(${IPaddr1} ${IPaddr2} ${IPaddr3} ${IPaddr4})
> >
> > myIpExec is a c program that normally uses scanf to prompt the user
> > for the IP addresses and returns 0 or 1.
> > I plan to use the script to test the program for various inputs.
> 
> It is more likely that this would work:
> 
> Result=$(echo "{IPaddr1} ${IPaddr2} ${IPaddr3} ${IPaddr4}" | myIpExec)
> 
> Note that there are no spaces around the equal sign.

  If the result of 'myIpExec' is output to stdout then you could put that into
a shell variable with the syntax that DennisW showed you.  But you may have a
problem with parsing it because any prompt for the IP addresses will be included
at the front of that variable.

  If the result of 'myIpExec' is actually a return value from main() then you
would access that as the shell variable $? just after the program is run.

  The bash 'here string' notation could be used as an alternative to the
echo pipeline notation.  It is not as portable.  But I like the way it looks
in shell script.  It is used like this-

myIpExec <<< "{IPaddr1} ${IPaddr2} ${IPaddr3} ${IPaddr4}"
Result=$?

-- 
Mike Stroyan <mike@stroyan.net>