Set environment variables

Environment variables are used by many programs to read in additional information at startup. E.g. the PATH environment variable tells the shell where to look for executables, thus allowing you to run many programs without having to specify the full path of the binary.

Windows NT and its successors know two types of environment variables: System variables can be changed only by the administrator and affect all users, whereas user variables affect only the user who set them for his own environment. Both are set in the System applet of the System settings group. Select the "Environment" tab in the pop-up dialog and click on the entry that you want to edit. The present value of the variable will be displayed in a separate edit field. Change the value or append new values to the semicolon-separated list. Click Set (clicking OK alone is not sufficient). To create a new environment variable, enter a new name into the provided edit field, and set a value as described above.

For Emacs as well as for command line windows, the environment variables are evaluated only once: when the window is opened first. If you change environment variables as described, they will have no effect on command line windows that are already open. So to see the effects of added or changed environment variables, you'll have to close and reopen any command line windows.

On Windows 95/98/ME, all environment variables are set in the autoexec.bat file with an entry like set VARIABLE=VALUE. You will have to reboot the computer to let the changes take effect.