Check if the caller of a script is also an owner of the script

check_caller

#!/bin/bash

true=0
false=1

##
# check if the caller is the same as the owner of the current script
# otherwise the following problem is possible:
# root calls you script and creates a file with root ownership
# then you need root to do anythink with the file

checkCaller()
{
    correctUser=`ls -nl $0 | awk '{print $3}'`

    echo $correctUser
    echo $UID

    [[ $correctUser == $UID ]]
}

# sample usage
checkCaller

if [[ $? -eq $false ]]; then
    echo "Error. Only owner of the script may run it. Please use su command!"
    exit $false
fi