%META:TOPICINFO{author="TWikiContributor" date="1170581173" format="1.1" version="1"}%
%META:TOPICPARENT{name="TWikiVariables"}%
#VarENV
---+++ 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: =%<nop>ENV{MOD_PERL}%= displays as: %ENV{MOD_PERL}%
   * If a variable is undefined (as against being set to the empty string) it will be returned as =not set=.
   * Related: [[%IF{"'%INCLUDINGTOPIC%'='TWikiVariables'" then="#"}%VarHTTPHOST][HTTP_HOST]], [[%IF{"'%INCLUDINGTOPIC%'='TWikiVariables'" then="#"}%VarREMOTEADDR][REMOTE_ADDR]], [[%IF{"'%INCLUDINGTOPIC%'='TWikiVariables'" then="#"}%VarREMOTEPORT][REMOTE_PORT]], [[%IF{"'%INCLUDINGTOPIC%'='TWikiVariables'" then="#"}%VarREMOTEUSER][REMOTE_USER]]
