feat: add all-in-one artifacts download command, per workflow

jekyll/_cci2/artifacts.adoc

@@ -168,6 +168,26 @@ Similarly, if you want to download the _latest_ artifacts of a build, replace th
 curl -H "Circle-Token: <circle-token>" https://circleci.com/api/v1.1/project/:vcs-type/:username/:project/latest/artifacts
 ----
 
+In some cases, you may need to download all artefacts from an entire workflow in one time. Having the workflow ID, possibly using the URL, you can use:
+
+[,shell]
+----
+# Set an environment variable for your API token.
+export CIRCLE_TOKEN=':your_token'
+
+# `curl` retrieve the list of jobs in the workflow,
+# then `jq` lists from the result and filter the job identifiers,
+# then `xargs`/`curl` generates the jobs URLs including the jobs identifiers,
+# then the result is piped into `grep` to extract the URLs,
+# finally, `wget` is used to download the artifacts to the current directory in your terminal.
+
+curl --silent --request GET --url https://circleci.com/api/v2/workflow/:workflow_id/job --header "Circle-Token: $CIRCLE_TOKEN" \
+  | jq '.items[].job_number' \
+  | xargs -I {} curl --silent --request GET --url 'https://circleci.com/api/v2/project/:vcs/:org/:project/{}/artifacts' --header "Circle-Token: $CIRCLE_TOKEN" \
+  | grep -o -E 'https://([^"]*)' \
+  | wget --verbose --header "Circle-Token: $CIRCLE_TOKEN" --no-verbose --input-file -
+----
+
 You can read more about using CircleCI's API to interact with artifacts in our link:https://circleci.com/docs/api/v1/#artifacts[API reference guide].
 
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