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+Atomically transfer a key from a source Redis instance to a destination Redis
+instance. On success the key is deleted from the original instance and is
+guaranteed to exist in the target instance.
+
+The command is atomic and blocks the two instances for the time required to
+transfer the key, at any given time the key will appear to exist in a given
+instance or in the other instance, unless a timeout error occurs. In 3.2 and
+above, multiple keys can be pipelined in a single call to `MIGRATE` by passing
+the empty string ("") as key and adding the `KEYS` clause.
+
+The command internally uses `DUMP` to generate the serialized version of the key
+value, and `RESTORE` in order to synthesize the key in the target instance. The
+source instance acts as a client for the target instance. If the target instance
+returns OK to the `RESTORE` command, the source instance deletes the key using
+`DEL`.
+
+The timeout specifies the maximum idle time in any moment of the communication
+with the destination instance in milliseconds. This means that the operation
+does not need to be completed within the specified amount of milliseconds, but
+that the transfer should make progresses without blocking for more than the
+specified amount of milliseconds.
+
+`MIGRATE` needs to perform I/O operations and to honor the specified timeout.
+When there is an I/O error during the transfer or if the timeout is reached the
+operation is aborted and the special error - `IOERR` returned. When this happens
+the following two cases are possible:
+
+- The key may be on both the instances.
+- The key may be only in the source instance.
+
+It is not possible for the key to get lost in the event of a timeout, but the
+client calling `MIGRATE`, in the event of a timeout error, should check if the
+key is _also_ present in the target instance and act accordingly.
+
+When any other error is returned (starting with `ERR`) `MIGRATE` guarantees that
+the key is still only present in the originating instance (unless a key with the
+same name was also _already_ present on the target instance).
+
+If there are no keys to migrate in the source instance `NOKEY` is returned.
+Because missing keys are possible in normal conditions, from expiry for example,
+`NOKEY` isn't an error.
+
+## Migrating multiple keys with a single command call
+
+Starting with Redis 3.0.6 `MIGRATE` supports a new bulk-migration mode that uses
+pipelining in order to migrate multiple keys between instances without incurring
+in the round trip time latency and other overheads that there are when moving
+each key with a single `MIGRATE` call.
+
+In order to enable this form, the `KEYS` option is used, and the normal _key_
+argument is set to an empty string. The actual key names will be provided after
+the `KEYS` argument itself, like in the following example:
+
+    MIGRATE 192.168.1.34 6379 "" 0 5000 KEYS key1 key2 key3
+
+When this form is used the `NOKEY` status code is only returned when none of the
+keys is present in the instance, otherwise the command is executed, even if just
+a single key exists.
+
+## Options
+
+- `COPY` -- Do not remove the key from the local instance.
+- `REPLACE` -- Replace existing key on the remote instance.
+- `KEYS` -- If the key argument is an empty string, the command will instead
+  migrate all the keys that follow the `KEYS` option (see the above section for
+  more info).
+- `AUTH` -- Authenticate with the given password to the remote instance.
+- `AUTH2` -- Authenticate with the given username and password pair (Redis 6 or
+  greater ACL auth style).
+
+`COPY` and `REPLACE` are available only in 3.0 and above. `KEYS` is available
+starting with Redis 3.0.6. `AUTH` is available starting with Redis 4.0.7.
+`AUTH2` is available starting with Redis 6.0.0.
+
+@return
+
+@simple-string-reply: The command returns OK on success, or `NOKEY` if no keys
+were found in the source instance.