ENV{"varname"} -- inspect the value of an environment variable

• Returns the current value of the environment variable in the CGI (Common Gateway Interface) environment. This is the environment that the TWiki scripts run in on the web server.
• Note: For security reasons, only those variables whose names match the regular expression in {AccessibleENV} in the Security Settings/Miscellaneous section of configure can be displayed. Any other variable will just be shown as an empty string, irrespective of its real value.
• Example: %ENV{MOD_PERL}% displays as: not set
• If a variable is undefined (as against being set to the empty string) it will be returned as not set.
• Related: HTTP_HOST, REMOTE_ADDR, REMOTE_PORT, REMOTE_USER