This is not a good way to respond to someone that was only trying to help you, especially on a community forum for an open source project, but frankly ever. You establish yourself as an adversary, and you reduce the likelihood that someone else will wade in and try to collaborate with you on finding a solution.
Here's a suggestion for a better response for you in the future: "okay, how do I find the path to apply that to?"
I see no indication in this thread that you read that article. Your assertion that it is useless is a stretch as if you knew what path to apply the tool to then you could use the documentation on that page to get out of this mess. Therefore, I agree with you that the only challenge here is finding that path.
Let me try to help you with that. You have the index name. You can hit /_cat/indices?v. This will give you a response like:
health status index uuid pri rep docs.count docs.deleted store.size pri.store.size
yellow open logstash-2017.04.09 qmDPqIHJTlmc-b9CB-gHSQ 5 1 0 0 985b 985b
That uuid is what you're looking for to get the path on disk. So in this case it would be nodes/0/indices/qmDPqIHJTlmc-b9CB-gHSQ/ relative to your data path.
Next, from shard id [[logstash-2017.04.09][0] we know that this is shard 0. Thus, the full path would be nodes/0/indices/qmDPqIHJTlmc-b9CB-gHSQ/0/translog so I would run:
$ bin/elasticsearch-translog truncate -d data/nodes/0/indices/qmDPqIHJTlmc-b9CB-gHSQ/0/translog/
We are going to improve this, so that it's easier to find the path. You can follow this on #24929.
Does that help?