`tk env list -l foo=bar` should exit with non-zero code when nothing is found

[bcbrockway]

As per the title, it would be nice for scripting if the command tk env list -l foo=bar exited with a non-zero code when it can't find anything using the selectors you input. Same logic as for grep basically.

[julienduchesne]

The --json option allows to script that. Example:

[[ "$(tk env list --json -l foo=bar | jq length)" == 0 ]] && echo "0 results" || echo "found envs"

You can get rid of jq by testing for the brackets directly also:

[[ "$(tk env list --json -l foo=bar)" == "[]" ]] && echo "0 results" || echo "found envs"