PEAR_ENV.reg question

Here's a snippet of code from PEAR_ENV.reg: REGEDIT4 [HKEY_CURRENT_USER\Environment] "PHP_PEAR_SYSCONF_DIR"="C:\\path\\to\\php" Correct me if I'm wrong, but shouldn't typing echo %PHP_PEAR_SYSCONF_DIR% in the Windows command line yield output of C:\path\to\php? When I try to do it, I get %PHP_PEAR_SYSCONF_DIR%, which suggests that %PHP_PEAR_SYSCONF_DIR% isn't an environmental variable even though the above registry modification makes me think that it is. This makes me wonder what the above registry modification actually does. Any ideas?