What is the best way to create a global environment variable in linux?

Question

linux

need to create a global environment variable in linux [debian based distro] via setup script

Answer 1

1 , 2 .

Answer 2

Write it down in /etc/environment, there is nowhere more global

Answer 3

Create temporary variable (local):

TEST_VAR=value
echo $TEST_VAR

Install "globally":

echo "export TEST_VAR='value' " >>  ~/.bashrc
source ~/.bashrc

Check:
env | grep TEST_VAR