$ concurrently --teardown "echo bye" "echo hey"
[0] hey
[0] echo hey exited with code 0
--> Running teardown command "echo bye"
bye
--> Teardown command "echo bye" exited with code 0

$ concurrently --teardown "echo bye" --teardown "echo real bye" "echo hey"
[0] hey
[0] echo hey exited with code 0
--> Running teardown command "echo bye"
bye
--> Teardown command "echo bye" exited with code 0
--> Running teardown command "echo real bye"
real bye
--> Teardown command "echo real bye" exited with code 0

$ concurrently --teardown "exit 1" "echo hey"
[0] hey
[0] echo hey exited with code 0
--> Running teardown command "exit 1"
--> Teardown command "exit 1" exited with code 1

$ echo $?
0