System information (version)

• OpenCV => 4.1.0
• Operating System / Platform => Ubuntu
• Compiler => N/A but gcc, g++

Detailed description

OpenCV install instructions in the docs asks users to install non-existent libraries. See: https://docs.opencv.org/4.1.0/d2/de6/tutorial_py_setup_in_ubuntu.html

The following libraries don't exist in the default Ubuntu apt-get repositories:
[What they are] -> [What they should be]
python-devel -> python-dev
numpy -> python-numpy
gcc -> OK
gcc-c++ -> g++
gtk2-devel
ffmpeg-devel
gstreamer-plugins-base-devel
libpng-devel
libjpeg-turbo-devel
jasper-devel
openexr-devel
libtiff-devel
libwebp-devel