The command env typed in your command prompt or Cygwin terminal will list the entire set of environment variables and their current values. My Computer –> Properties –> Advanced –> Environment Variables will also show you the Windows environment variables divided into two categories: System variables and User variables.

While on cmd each variable can be referred to using %ENVIRONMENT-VARIABLE%, on Cygwin and all Unix-based OSs they are referred to using $ENVIRONMENT-VARIABLE. ($ echo %ENVIRONMENT-VARIABLE% or $ echo $ENVIRONMENT-VARIABLE)

ALLUSERSPROFILE, APPDATA, COMPUTERNAME, HOMEDRIVE, HOMEPATH, PATH, PROGRAMFILES, SYSTEMDRIVE, SystemRoot, USERNAME, USERPROFILE, WINDOWS are a some important environment variables some of which may be modified and are usually quite useful while writing batch programs. OS, NUMBER_OF_PROCESSORS, PROCESSOR_ARCHITECTURE, PROCESSOR_IDENTIFIER, PROCESSOR_LEVEL are a few other interesting variables which are best left untouched.

$ set ENVIRONMENT-VARIABLE=value can be used to change an existing or define a new environment variable.

Image Source: Microsoft Windows on my desktop.

Post from: EveryJoe

Environment Variables