Why pipeline environment var not work

I wanna to get the evironment value
Then, i did like this:

but it output this:

Can anyone give me some advice? Thank you.

Check this: https://stackoverflow.com/questions/41881713/drone-replacing-environment-variables-with-empty-strings

Use environment vars like this $my_env_var instead

it is still not worked for me , i tried this

then, it output $banch_dev

this is because drone emulates bash string substitution using a Go library that we created. Only these environment variables can be used in yaml substitution: https://docs.drone.io/reference/environ/