错误现象：

终端显示如下：-bash: mysql: command not found

原因：这是由于系统默认会查找/usr/bin下的命令，如果这个命令不在这个目录下，当然就找不到命令

解决方法：

我们需要做的就是映射一个链接到/usr/bin目录下，相当于建立一个链接文件。
1. 知道mysql命令或mysqladmin命令的完整路径，比如mysql的路径是：/usr/local/mysql/bin/mysql，

2. 执行命令：$sudo ln -s /usr/local/mysql/bin/mysql /usr/bin

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忘记mysql密码可进行如下操作，楼主用的mac os x：

先把mysql服务关掉，然后执行过程如下：

TT-MacBook-Air:~ jasonyao$ sudo mysqld_safe --skip-grant-table &
[1] 1182
TT-MacBook-Air:~ jasonyao$ 140402 20:10:58 mysqld_safe Logging to '/usr/local/mysql/data/TT-MacBook-Air.err'.
140402 20:10:58 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data
mysql -u root mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 21
Server version: 5.6.17 MySQL Community Server (GPL)

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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> update user set password=PASSWORD('new password') where user='root';
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4  Changed: 4  Warnings: 0

mysql> commit;
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> commit;
Query OK, 0 rows affected (0.01 sec)

mysql>