OpenCV_createsamples: command not found error

Hello all,
When i try to run the code i made with the HaarCascase method on the terminal screen, i get the following error.

Code end error;

opencv_createsamples -info pozitif.txt -num 50 -vec pozitifResim.vec -w 24 -h 24
bash: opencv_createsamples: command not found

My current OpenCV versions is 4.1.1. What should i do?
Thanks in advance.

Please check this post.

How can i downgrade the current version?