#! /bin/bash age=60 # for using And operator use && if [ "$age" -gt 18] && ["$age" -lt 30 ] then echo "valid age" else echo "age not valid" fi # The -a option provide # an alternative compound condition test. if [ "$age" -gt 18 -a "$age" -lt 30 ] then echo "valid age" else echo "age not valid" fi # if [[ $condition1 && $condition2 ]] # Also works. if [[ "$age" -gt 18 && "$age" -lt 30 ]] then echo "valid age" else echo "age not valid" fi