:main
@echo off
echo this is main
call :sub1 from main
call :sub1 from main, 2nd time
goto :eof

:sub1
echo this is sub1. Message: %*
goto :eof

@echo off

rem *** enable !variable!
setlocal enabledelayedexpansion

for %%i in (1,2,3,4,5,6,7,8,9) do (
    set A=%%i
    rem it doesn't work as expected
    echo %A%
)
echo value of a after 1st loop %A%

for %%i in (1,2,3,4,5,6,7,8,9) do (
    set A=%%i
    rem it works as expected
    echo !A!
)
echo value of a after 2nd loop %A%

@echo off

set var1=d:\sharedFolder
echo \\%machinename%\%var1::=$%
echo %var1:~0,3%

@echo off

set var1=0

set /a var1+=3
echo %var1%

set /a var1*=5
echo %var1%

set var2=10
set /a var1=var2+var1
echo %var1%