.sh check for numeric content

[Aiza]

Thomas wrote:
> On Thu, Jun 24, 2010 at 09:24:39AM +0800, Aiza wrote:
> 
> Hello,
> 
>> Receiving a variable from the command line that is suppose
>> to contain numeric values.
>>
>> How do I code a test to verify the content is  numeric?
> 
> http://www.google.com/search?q=shell+test+if+variable+numeric
> 
> First link =>
> http://www.unix.com/shell-programming-scripting/46276-check-variable-if-its-non-numeric.html
> 
> Gosh, Google is full of answers these days..
> 

yea but none of them are for freebsd style .sh shell


I'm, using

[ "${dup_times}" != [0-9] ] && exerr "value not numeric"

and get the errot messahe no mater what value is in dup_times.

What is wrong with this code?