integer_detection.sh

#!/bin.bash

regex='^[0-9]+$'

foo='1234'
bar='hi bean'

echo "foo = $foo"

if [[ "$foo" =~ $regex ]]; then
    echo "$foo is an integer"
else
    echo "$foo is a string"
fi

echo "bar = $bar"

if [[ "$bar" =~ $regex ]]; then
    echo "$bar is an integer"
else
    echo "$bar is a string"
fi