How to check if a number is within a range in shell

Question

I want to just insert number between two values, and otherwise the script repeated until correct number.

This is my script and it does not work correctly:

validation(){ read number if [ $number -ge 2 && $number -ls 5 ]; then     echo "valid number"     break else     echo "not valid number, try again" fi  }  echo "insert number" validation echo "your number is" $number 

Answer 1

If you are using Bash, you are better off using the arithmetic expression, ((...)) for readability and flexibility:

if ((number >= 2 && number <= 5)); then   # your code fi 

To read in a loop until a valid number is entered:

#!/bin/bash  while :; do   read -p "Enter a number between 2 and 5: " number   [[ $number =~ ^[0-9]+$ ]] || { echo "Enter a valid number"; continue; }   if ((number >= 2 && number <= 5)); then     echo "valid number"     break   else     echo "number out of range, try again"   fi done 

((number >= 2 && number <= 5)) can also be written as ((2 <= number <= 5)).

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See also:

• Test whether string is a valid integer
• How to use double or single brackets, parentheses, curly braces

Answer 2

Your if statement:

if [ $number -ge 2 && $number -ls 5 ]; then  

should be:

if [ "$number" -ge 2 ] && [ "$number" -le 5 ]; then 

Changes made:

• Quoting variables is considered good practice.
• ls is not a valid comparison operator, use le.
• Separate single-bracket conditional expressions with &&.

Also you need a shebang in the first line of your script: #!/usr/bin/env bash