I want to check whether the variable read from the console is number or character , so i used echo $option|grep [0-9] and checked the reuslt returned by grep cmd using $?

But since I use echo the value is getting printed in the screen , I want to supress the o/p. Can anyone suggest how this can be done .

I am new to unix so I dont knowif there is any function thro which we can check if the variable is number or string .... pls help me in this regard

Use the search feature. How to check whether a string is number or not