printenv

List the names and values of all environment variables or, with name, the value of the environment variable name.

Syntax
      printenv [name]
	       
Options
      name  The name of the environment variable

“Everything you read in newspapers is absolutely true, except for that rare story of which you happen to have first-hand knowledge” - Erwin Knoll

Related:

printenv page - Apple.com
env - Display, set, or remove environment variables
set - Manipulate shell variables and functions