➜ cd /usr/local/mysql/bin

➜ bin sudo su

sh-3.2# ./mysqld_safe --skip-grant-tables &
[1] 9451
sh-3.2# 2017-01-03T15:40:10.6NZ mysqld_safe Logging to '/usr/local/mysql/data/yzydeMacBook-Pro.local.err'.
2017-01-03T15:40:10.6NZ mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data

./mysql -uroot
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 2
Server version: 5.7.12 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed

mysql> show tables;
+---------------------------+
| Tables_in_mysql   |
+---------------------------+
| columns_priv    |
| db      |
| engine_cost    |
| event      |
| func      |
| general_log    |
| gtid_executed    |
| help_category    |
| help_keyword    |
| help_relation    |
| help_topic    |
| innodb_index_stats  |
| innodb_table_stats  |
| ndb_binlog_index   |
| plugin     |
| proc      |
| procs_priv    |
| proxies_priv    |
| server_cost    |
| servers     |
| slave_master_info   |
| slave_relay_log_info  |
| slave_worker_info   |
| slow_log     |
| tables_priv    |
| time_zone     |
| time_zone_leap_second  |
| time_zone_name   |
| time_zone_transition  |
| time_zone_transition_type |
| user      |
+---------------------------+
31 rows in set (0.00 sec)

mysql> show columns from user;
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field     | Type        | Null | Key | Default    | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Host     | char(60)       | NO | PRI |      |  |
| User     | char(32)       | NO | PRI |      |  |
| Select_priv   | enum('N','Y')      | NO |  | N      |  |
| Insert_priv   | enum('N','Y')      | NO |  | N      |  |
| Update_priv   | enum('N','Y')      | NO |  | N      |  |
| Delete_priv   | enum('N','Y')      | NO |  | N      |  |
| Create_priv   | enum('N','Y')      | NO |  | N      |  |
| Drop_priv    | enum('N','Y')      | NO |  | N      |  |
| Reload_priv   | enum('N','Y')      | NO |  | N      |  |
| Shutdown_priv   | enum('N','Y')      | NO |  | N      |  |
| Process_priv   | enum('N','Y')      | NO |  | N      |  |
| File_priv    | enum('N','Y')      | NO |  | N      |  |
| Grant_priv    | enum('N','Y')      | NO |  | N      |  |
| References_priv  | enum('N','Y')      | NO |  | N      |  |
| Index_priv    | enum('N','Y')      | NO |  | N      |  |
| Alter_priv    | enum('N','Y')      | NO |  | N      |  |
| Show_db_priv   | enum('N','Y')      | NO |  | N      |  |
| Super_priv    | enum('N','Y')      | NO |  | N      |  |
| Create_tmp_table_priv | enum('N','Y')      | NO |  | N      |  |
| Lock_tables_priv  | enum('N','Y')      | NO |  | N      |  |
| Execute_priv   | enum('N','Y')      | NO |  | N      |  |
| Repl_slave_priv  | enum('N','Y')      | NO |  | N      |  |
| Repl_client_priv  | enum('N','Y')      | NO |  | N      |  |
| Create_view_priv  | enum('N','Y')      | NO |  | N      |  |
| Show_view_priv   | enum('N','Y')      | NO |  | N      |  |
| Create_routine_priv | enum('N','Y')      | NO |  | N      |  |
| Alter_routine_priv  | enum('N','Y')      | NO |  | N      |  |
| Create_user_priv  | enum('N','Y')      | NO |  | N      |  |
| Event_priv    | enum('N','Y')      | NO |  | N      |  |
| Trigger_priv   | enum('N','Y')      | NO |  | N      |  |
| Create_tablespace_priv | enum('N','Y')      | NO |  | N      |  |
| ssl_type    | enum('','ANY','X509','SPECIFIED') | NO |  |      |  |
| ssl_cipher    | blob        | NO |  | NULL     |  |
| x509_issuer   | blob        | NO |  | NULL     |  |
| x509_subject   | blob        | NO |  | NULL     |  |
| max_questions   | int(11) unsigned     | NO |  | 0      |  |
| max_updates   | int(11) unsigned     | NO |  | 0      |  |
| max_connections  | int(11) unsigned     | NO |  | 0      |  |
| max_user_connections | int(11) unsigned     | NO |  | 0      |  |
| plugin     | char(64)       | NO |  | mysql_native_password |  |
| authentication_string | text        | YES |  | NULL     |  |
| password_expired  | enum('N','Y')      | NO |  | N      |  |
| password_last_changed | timestamp       | YES |  | NULL     |  |
| password_lifetime  | smallint(5) unsigned    | YES |  | NULL     |  |
| account_locked   | enum('N','Y')      | NO |  | N      |  |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
45 rows in set (0.02 sec)

mysql> select authentication_string from user where User='root';
+-------------------------------------------+
| authentication_string      |
+-------------------------------------------+
| *781D25322166DB7FF99BA4A1FA5ED30439A60DDE |
+-------------------------------------------+
1 row in set (0.01 sec)