While working with java or python many of the times we may come across error of “command not found” while executing command in cmd, even after proper installation of the software.
For python while trying to install a package through command prompt (cmd) following error may be faced:

This error can be recovered by adding the path of python to system’s environment variables list by following the below steps:

1. To add or edit anything environment variables in Windows 7, go to System Properties first.
   
   

   Fig2: Open system settings

   

   Fig3: Open Systems settings

2. Go to “Advanced” tab and in that open environment variables:
   
   

   Fig4: Open environment variables

3. Select “Path” under Variable column and press “edit” button:
   
   

   Fig5: Edit variable path

   Note that you have to enter variable path separated by “;”, i.e. for python 2.7 you need to add “C:\Python27\;C:\Python27\Scripts;”

Install python 2.7.13 with image processing tool OpenCV.