Hi

how to check input is "empty" and "numeric" in ksh?

e.g:
./myscript.ksh k
output show: invalid number input

./myscript.ksh
output show: no input

./myscript.ksh 10
output show: input is numeric

checking for empty is easy

if test "$VAR" = ""
then 
    echo empty
fi

case "$VAR" in
[0-9]* )
         echo at least it starts with a numeric...
        ;;
* )
       ;;
esac

thanks. is working fine.

If you want to be sure the entire argument is numeric (rather than just the first character), use grep:

if echo $VAR | grep [^0-9] > /dev/null
then
  echo "Some non-numeric characters detected"
else
  echo "All numeric"
fi

The case statement itself can manage full numeric check (for both integers and floating point numbers):

HTH

this is the best +([0-9])*(.)*([0-9]) )