printenv prints environment variable values. Synopsis:
printenv [option] [variable]...
If no variables are specified, printenv prints the value of every environment variable. Otherwise, it prints the value of each variable that is set, and nothing for those that are not set.
The program accepts the following option. Also see Common options.
0 if all variables specified were found 1 if at least one specified variable was not found 2 if a write error occurred