groups_to_tags.sh

#!/usr/bin/env bash

# Depends on curl and jq
# jq: https://stedolan.github.io/jq/
#
# LINODE_API_KEY must be set to v3 API key
# LINODE_API_TOKEN must be set to v4 API token

# !!!! WARNING !!!!
# This will overwrite any tags you already have made
# It prompts you, but still...
# !!!! WARNING !!!!

update_tags() {
    curl -s https://api.linode.com/?api_key=${LINODE_API_KEY}\&api_action=linode.list | jq -r '.DATA[] | [.LINODEID, .LPM_DISPLAYGROUP] | @csv' \
        | while IFS=, read -r linode_id linode_group; do
            curl -s -X PUT \
                 -H "Content-Type: application/json" \
                 -H "Authorization: Bearer ${LINODE_API_TOKEN}" \
                 -X PUT -d "{\"tags\": [${linode_group}]}" \
                 https://api.linode.com/v4/linode/instances/${linode_id} \
            | jq -r '"\(.id) \(.label) \(.tags)"'
          done
}

echo "This will overwrite any existing tags."
read -p "Do you want to continue (y/n)? " choice
case "${choice}" in
    y|Y ) update_tags;;
    n|N ) echo "Bailing out";;
    * ) echo "That isn't what I asked for, but I'm bailing anyway. Please try again.";;
esac