How to define a variable in a TCSH script that will not be exported to the process which invoked it

To pull the effective uid use this command:

id -u

If the result is ‘0’ then the script is either running as root, or using sudo. You can run the check by doing something like:

if [[ $(/usr/bin/id -u) -ne 0 ]]; then
    echo "Not running as root"
    exit
fi

You really should move away from Batch files.

@echo off

setlocal enabledelayedexpansion

set x=100
set result=0

for /L %%i in (1,1,5) do (

  set /A result=!x! + %%i

  echo !result!
)

endlocal