1.1. help

$  etcdctl migrate --help
NAME:
        migrate - Migrates keys in a v2 store to a mvcc store

USAGE:
        etcdctl migrate [flags]

OPTIONS:
      --data-dir=""     Path to the data directory
  -h, --help[=false]    help for migrate
      --no-ttl[=false]  Do not convert TTL keys
      --transformer=""  Path to the user-provided transformer program
      --wal-dir=""      Path to the WAL directory