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.
  • Category: SystemInformationVariables
  • Related: HTTP_HOST, REMOTE_ADDR, REMOTE_PORT, REMOTE_USER