oleg@oleg-MS-7918:~$ cd /usr/local/include/opencv4/ oleg@oleg-MS-7918:/usr/local/include/opencv4$ ls opencv2 oleg@oleg-MS-7918:/usr/local/include/opencv4$ cp -r opencv2/ .. cp: cannot create directory '../opencv2': Permission denied
g++ main.cpp -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_imgcodecs -lopencv_videoio -lopencv_features2d -lopencv_ml -lopencv_objdetect -lopencv_calib3d -lopencv_video
LD_LIBRARY_PATH=/usr/local/lib ./a.out