system("ls && ls") should work in windows
Since windows "on the command line" supports &&, I believe this should work for ruby system commands.
It appears this run both commands, as expected (the first one fails):
using "||" works well:
system("ffmpeg -i || ls") # ffmpeg -i fails
system("ls && ls")
ls: &&: No such file or directory
ls: ls: No such file or directory