I have a terminal-command like this
convert images/keke_input.png -crop 50x100%+0+0 \( +clone -flop \) +append images/keke_output.png
//It's works like flop with [THIS][HALF], but i need to use flop with [HALF][THIS].
convert input.jpg -crop 50x100% -delete 0 ...
That will crop the image into 2 equal pieces, each one half of the full width. Then delete the first half and you will be left with the second.
So, if you start with this:
you will get this:
So, the full command would be:
convert input.jpg -crop 50x100% -delete 0 \( +clone -flop \) +append result.jpg