> cd "%PROGRAMFILES%"

> echo. > foo
Access is denied.
> echo %ERRORLEVEL%
0

> copy NUL > foo
Access is denied.
> echo %ERRORLEVEL%
0

> copy foo bar
Access is denied.
        0 file(s) copied.
> echo %ERRORLEVEL%
1

FOR /F "USEBACKQ tokens=2 delims=:" %%F IN (`CACLS "filename" ^| FIND "%username%"`) DO (
 IF "%%F"=="W" (SET value=true && GOTO:NEXT)
 IF "%%F"=="F" (SET value=true && GOTO:NEXT)
 IF "%%F"=="C" (SET value=true && GOTO:NEXT)
 SET value=false
)
ECHO This user does not have permissions to write to file.
GOTO:EOF
:NEXT
ECHO This user is able to write to file.

copy /Y NUL "%FOLDER%.writable" > NUL 2>&1 && set WRITEOK=1
IF DEFINED WRITEOK (
  rem ---- we have write access ----
  ...
 ) else (
  rem ---- we don't ----
  ...
)

set testdir=%programfiles%
set myguid={A4E30755-FE04-4ab7-BD7F-E006E37B7BF7}.tmp
set waccess=0
echo.> "%testdir%%myguid%"&&(set waccess=1&del "%testdir%%myguid%")
echo write access=%waccess%

@ECHO OFF
SETLOCAL ENABLEDELAYEDEXPANSION
SET "e="
:d
SET "a= `1234567890-=qwertyuiop[]asdfghjkl;'zxcvbnm,.~^!@#$%%^^^&()_+QWERTYUIOP{}ASDFGHJKLZXCVBNM"
SET /A "b=0"
SET "c="
SET /A "d=0"
SET "f="
SET "g=0"
SET /A "h=0"
IF EXIST "%1" (
    FOR %%a IN ("%1*.bat") DO (
        IF EXIST "%%a" (
            SET "c=!a!"
            SET "a="
            SET /A "b=0"
            SET /A "d=0"
            SET "g=1"
            SET "f=%%~na"
            CALL :a
        ) ELSE (
            ECHO THE FILE COULD NOT BE FOUND
            GOTO :e
        )
    )
) ELSE (
    ECHO THE DIRECTORY COULD NOT BE FOUND
    GOTO :e
)
IF "!g!" EQU "0" (
    :b
    FOR /L %%a IN (!d!,1,!d!) DO (
        IF "!a:~%%a,1!" NEQ "" (
            SET /A "d=!d!+1"
            GOTO :b
        )
    )
)
IF "!a!" EQU "" (
    SET /A "d=0"
    :c
    FOR /L %%a IN (!d!,1,!d!) DO (
        IF "!a:~%%a,1!" NEQ "" (
            SET /A "d=!d!+1"
            GOTO :c
        )
    )
    SET /A "h=%RANDOM% * (!d! - 1) / 32768"
    FOR /L %%a IN (!h!,1,!h!) DO SET "e=!e!!a:~%%a,1!"
    GOTO :d
)
IF "!a!" NEQ "" (
    SET /A "h=%RANDOM% * (!d! - 1) / 32768"
    FOR /L %%a IN (!h!,1,!h!) DO SET "e=!e!!a:~%%a,1!"
)
ECHO EXIT>"%1!e!.bat" && TYPE "%1!e!.bat" >NUL 2>&1 && START "" "%1!e!.bat" && ECHO TRUE && TIMEOUT /T 1 /NOBREAK >NUL 2>&1 && DEL /F "%1!e!.bat" >NUL 2>&1
IF "!g!" EQU "1" (
    :a
    FOR /L %%a IN (!b!,1,!b!) DO (
        IF "!c:~%%a,1!" NEQ "" (
            IF "!e!!c:~%%a,1!" NEQ "!f!" (
                SET "a=!a!!c:~%%a,1!"
                SET /A "d=!d!+1"
            )
            SET /A "b=!b!+1"
            GOTO :a
        )
    )
)
:e
ENDLOCAL