Using environment variables basic settings in the operating system can be made. Such settings can be determined in various ways:
These levels are organized hierarchically, so that settings can be made in all levels. The declaration in the command line has the highest precedence. Then the value of the environment variable in the process environment is considered. If there are no declarations in these two levels, the entries in the Microsoft Windows Registry are used.
Often it is necessary to overwrite existing settings. This can be done via the command line, or, if this is not possible, via a SET command.