[batch-file] How can I check the size of a file in a Windows batch script?

You'll need two things.

filesize.bat 

@echo off
echo %~z1

And then what you're actually trying to size up.

Copy a file only if it's larger than zero / copy only a non-zero file

for /f %i in ('filesize filesize.bat') do set z=%i
if %z% gtr 0 ( copy filesize.bat noodles.bat )

I found this thread and it was almost what I needed, I tried a bunch of different things - this was mildly frustrating because robocopy looked to have /min:1 but got ALL bunged up because I wanted to rename the file in transit which made me have to use @#$!! batch script.