How to use % or ! in batch script - windows

Question

I write script like this:
#ECHO OFF
setlocal EnableDelayedExpansion
set "remove=ABC"
echo. %remove%
Set FILENAME="456_789_ABC00011092_789_EFGHIK_56893.mpg"
for %%a in (%FILENAME:_=" "%) do (
set TEN=%%a
echo. %AB%
set "remove_1=ABC"
echo. %remove_1%
Set _TEN=!TEN:%remove%=!
echo. %_TEN%
Set i=0
IF !_TEN! NEQ !TEN! (
set /A i+=1
set "String[!i!]=%%~a"
)
)
pause
exit
Why echo. %AB% echo. %remove_1% result is
I replace % by !. It's work fine but command Set _TEN=!TEN:!remove_1!=! not run
Edit - (from the additional question currently posted as an answer)
When I use FindStr command like this:
for %%a in (%FILENAME:_=" "%) do (
echo %%a | findstr /I /R /C:"ABC" >nul
ECHO %errorlevel%
if "%errorlevel%" equ "0" (
set /A i+=1
set "String[!i!]=%%~a"
)
)
Why errorlevel always = 0

Answer 1

%AB% has not been defined within your posted script, so as it has no value will not be echoed, you will just get an empty line due to the . after echo. Because remove_1 is being set within the loop, (code block), you should be using the delayed expansion syntax, Echo !remove_1!. It is the same for echo. %_TEN%, i.e. Echo !_TEN!, and would have been Echo !AB! had it previously been defined. In order to get the double expansion needed to Set your _TEN variable, you could use a pseudo Call:
#Echo Off
SetLocal EnableDelayedExpansion
Set "FILENAME=456_789_ABC00011092_789_EFGHIK_56893.mpg"
For %%A In ("%FILENAME:_=" "%") Do (
Set "TEN=%%A"
Echo. !AB!
Set "remove_1=ABC"
Echo !remove_1!
Call Set "_TEN=!TEN:%%remove_1%%=!"
Echo !_TEN!
Set "i=0"
If "!_TEN!" NEq "!TEN!" (
Set /A i+=1
Set "String[!i!]=%%~A"
)
)
Pause
Exit /B
In your second related question, initially posted as an answer and now added as an edit to your original question; because the error level is being set within the loop, (code block), you should be using the delayed expansion syntax, !errorlevel!
#Echo Off
SetLocal EnableDelayedExpansion
Set "FILENAME=456_789_ABC00011092_789_EFGHIK_56893.mpg"
For %%A In ("%FILENAME:_=" "%") Do (
Echo %%A | FindStr /IRC:"ABC" >Nul
Echo !errorlevel!
If "!errorlevel!"=="0" (
Set /A i+=1
Set "String[!i!]=%%~A"
)
)
Set String[
Pause
Exit /B
Or if you don't need to Echo each error level to the screen, you can use a conditional statement &&:
#Echo Off
SetLocal EnableDelayedExpansion
Set "FILENAME=456_789_ABC00011092_789_EFGHIK_56893.mpg"
For %%A In ("%FILENAME:_=" "%") Do (
Echo %%A | FindStr /IRC:"ABC" >Nul && (
Set /A i+=1
Set "String[!i!]=%%~A"
)
)
Set String[
Pause
Exit /B