Why is same privileged bash command giving different information from script than from command line?

Question

I wrote a bash script to verify various configs on a system, but I am getting different results depending on whether it is run from the command line directly or from the script. Here is the command:

bt_discoverable=$(system_profiler SPBluetoothDataType | grep Discoverable) 

If I disable discoverable on the bluetooth and then echo the variable on the command line I get the expected result:

Discoverable: No 

But if I echo it immediately after running the same command from a bash script, I get

Discoverable: Yes 

The script does elevate its privileges through an internal sudo function, so I commented the block for that function out and ran the script again. This time, things worked as they should. Here is the elevation function:

RunAsRoot() { if [[ "${USER}" != "root" ]] ; then echo echo echo "*** Type the password for ${USER} and press ENTER ***" echo sudo $1 && exit 0 fi } RunAsRoot $0 

This function is the first thing the script runs, so the code position is a problem.

Why does running in an elevated privilege (sub)shell cause this issue? Is the problem Terminal, Bash, or something else I'm ignorant of?

Answer 1

The difference comes from the change in shell environment once elevated. I'm not sure how you would write a script that would account for this change easily, but the answer to my original question is that you need to be aware of such differences when you elevate privileges.

Thanks to "thankyour" for this lead. I finally posted this as an answer since they didn't for some weeks.

Answer 2

This is my workaround

bt_discoverable=$(system_profiler SPBluetoothDataType | grep Discoverable) sudoMe() { if [[ "${USER}" != "root" ]]; then echo "inside...as: $USER" sudo $0 && sudoBack fi } doAsRoot(){ if [[ "${USER}" == "root" ]]; then echo "this as $USER" fi } sudoBack(){ if [[ "${USER}" == "root" ]]; then echo "reverse...from: $USER" sudo -k && exit 0 fi } discover() { echo $bt_discoverable } sudoMe doAsRoot sudoBack discover 

1. sudoMe will elevate to root by calling the script again.
2. All following functions like doAsRoot must check for $USER == root, otherwise will run in first call of script as invoking $USER.
3. sudoBack will elevate down using sudo -k
4. All following functions like discover will now run as first $USER

If we invoke as root like in the answer, there is no way IMHO back with sudo -k in any part of the script. I tested, but couldn't find any ;-)