validate number range

Shell Programming and Scripting
1

Hi

If I want to read user input and want to validate if it is a numeric number in some range of 1-100 what would be the best way?

Sabina

2

You need to tell us which shell and what system. But for ksh this should work

print -n "enter number - "
read val
if [[ $val -ge 1 && $val -le 100 ]] ; then

3

hi

I am using bourne shell. I used your script it works as long as I enter a number.

I want it to fail if I enter a string by mistake.

Thanks for your reply.

Sabina

4 
print -n "enter number - "
read val

echo $val | grep "[a-zA-Z]"

if test $? -ge 1
then
   if [[ $val -ge 1 && $val -le 100 ]] ; then
     print "OK"
   else
     print "NOT in 1-100 range"
   fi
else
  print "Not a number"

fi
1 Like
5

A slight variation on bhargav's script to ensure that only numeric digits are passed, and symbols as well as letters are rejected....

#!/bin/sh

echo "Enter number"
read val

if echo $val | egrep '^[0-9]+$' >/dev/null 2>&1
then
  if [ $val -ge 1 -a $val -le 100 ]; then
     echo "OK"
  else
     echo "Out of range"
  fi
else
  echo "Not a number"
fi

exit 0

Cheers
ZB

1 Like
6

hi Zb and bhargav

Thanks a lot for your time. It was really useful.

Sabina