Launch a batch file without showing the window, within one file and without third-party tools

Hidden.bat

@echo off

if not "%1"=="Opened_Via_PS" (
    pushd %~dp0
    REM //TODO: Use Env variable instead of passing checking arg.
    rem Adopted from https://superuser.com/questions/62525/run-a-batch-file-in-a-completely-hidden-way
    rem The " ^" at the end is similar to " \" for multi-line scripts.
    rem Extend the %1 %2 (%3...) below if you have multiple command line args.
    powershell.exe -NoLogo -NoProfile -WindowStyle Hidden -NonInteractive -ExecutionPolicy Bypass -Command ^
    "(New-Object -ComObject WScript.Shell).Run('\"%cd%\%~n0%~x0\" Opened_Via_PS %1 %2', 0,  'false')"
    popd
    exit
)

rem %1 is used for "Opened_Via_PS" which check whether its opened via powershell above
set "arg1=%2"
set "arg2=%3"
rem ...and so on

rem Here you can put your stuff that can be hidden if its a commandline only tool.
echo "Normally you will see me, but now you cannot!"
notepad.exe %arg1%
msg * You closed the notepad.