Ubuntu 12.04 安装MySQL

本文地址：http://www.cnblogs.com/yhLinux/p/4012689.html

本文适合新手入门。

本文是对 Ubuntu 12.04 环境下安装 MySQL 的记录，通过这两天的折腾，不断试错，才发现要完整地掌握 MySQL 安装其实并不复杂，关键是遇到问题时记住到官方文档寻找解决方案，在网络上搜索的网友的方法不一定适合你，而官方文档是比较全面的，建议大家有问题多看看。

安装MySQL的方法有多种方式，包括源码安装，包管理器安装，二进制安装等。之前，我使用最快的方式——包管理器安装，但安装完成后，对MySQL的很多文件的作用完全是迷茫的，不知任何用处；而采用源码方式安装，又需要设置更多的编译选项，折中的办法是选择二进制安装，即Generic Binaries，在Linux下就主要分为三步完成(创建mysql用户，解压安装包，安装后设置)，看上去是不是和Windows下的绿色软件安装很像吧？而且，通过此安装配置过程，读者可以了解到 MySQL 安装布局，方便你轻松掌握 MySQL 的各类文件作用，对了解 MySQL 以快速入门有很大帮助。好了，废话不多说，开始安装 MySQL 吧。

 

Ubuntu12.04 以通用可执行文件(Generic Binaries)安装MySQL

目录：

　　1. 安装前准备工作

　　2. 安装

　　　　2.1. 安装概览

　　　　2.2. 安装详情

　　3. 对最初MySQL账户进行安全设置

　　4. 时区与环境变量设置

　　5. 附录

　　　　5.1 字符集设置

　　　　5.2 我的配置文件my.cnf

选择安装版本：

[http://dev.mysql.com/doc/refman/5.6/en/choosing-version.html]

Normally, if you are beginning to use MySQL for the first time or trying to port it to some system for which there is no binary distribution, use the most recent General Availability series listed in the preceding descriptions.由此，本文选择安装MySQL 5.6: Latest General Availability (Production) release

MySQL 安装选择上说：“We put a great deal of effort into ensuring that our binaries are built with the best possible options for optimal performance.”，由此可知，Generic Binaries安装有诸多优化，所以我们按此链接来做，Installing from a generic binary package in.tar.gzformat.

See Section 2.2, “Installing MySQL on Unix/Linux Using Generic Binaries” for more information.

下载http://dev.mysql.com/downloads/mysql/#current-tab，我的系统是64位的，对应Linux - Generic (glibc 2.5) (x86, 64-bit), Compressed TAR Archive，下载mysql-5.6.21-linux-glibc2.5-x86_64.tar.gz，md5值79f9a54bdc3731fd4bdf22db77f27ca7

Warning

If you have previously installed MySQL using your operating system native package management system, such as yum or apt-get, you may experience problems installing using a native binary. Make sure your previous MySQL previous installation has been removed entirely (using your package management system), and that any additional files, such as old versions of your data files, have also been removed. You should also check the existence of configuration files such as /etc/my.cnf or the /etc/mysql directory have been deleted.

sudo apt-get autoremove --purge mysql-server-5.5 
sudo apt-get remove mysql-server
sudo apt-get autoremove mysql-server
sudo apt-get remove mysql-common

Table 2.3 MySQL Installation Layout for Generic Unix/Linux Binary Package

Directory	Contents of Directory
bin	Client programs and the mysqld server
data	Log files, databases
docs	Manual in Info format
man	Unix manual pages
include	Include (header) files
lib	Libraries
scripts	mysql_install_db
share	Miscellaneous support files, including error messages, sample configuration files, SQL for database installation
sql-bench	Benchmarks

记得删除之前安装所残余的mysql文件，然后：

做完以上准备工作，现在我们来预览一下整个安装过程。

安装流程概览：

To install and use a MySQL binary distribution, the basic command sequence looks like this：

//Create a mysql User and Group
shell> groupadd mysql
shell> useradd -r -g mysql mysql

//Obtain and Unpack the Distribution
shell> cd /usr/local
shell> tar zxvf /path/to/mysql-VERSION-OS.tar.gz
shell> ln -s full-path-to-mysql-VERSION-OS mysql

//Perform Postinstallation Setup
shell> cd mysql
shell> chown -R mysql .
shell> chgrp -R mysql .

shell> apt-get install libaio1 libaio-dev
shell> ./scripts/mysql_install_db --user=mysql

shell> chown -R root .
shell> chown -R mysql data
shell> bin/mysqld_safe --user=mysql &
# Next command is optional
shell> cp support-files/mysql.server /etc/init.d/mysql.server

以上安装命令是全部的动作，一共分为三部分(创建mysql用户，解压安装包，安装后设置)，每一步骤的解释都有对应的官方文档，以下一步一步来做：

2.2 Installing MySQL on Unix/Linux Using Generic Binaries

//Create a mysql User and Group
shell> groupadd mysql
shell> useradd -r -g mysql mysql

//Obtain and Unpack the Distribution
shell> cd /usr/local
shell> tar zxvf /path/to/mysql-VERSION-OS.tar.gz
shell> ln -s full-path-to-mysql-VERSION-OS mysql

Section 2.10, “Postinstallation Setup and Testing”.

------------>2.10.1 Postinstallation Procedures for Unix-like Systems

//Perform Postinstallation Setup
1.
shell> cd mysql

2.（以root权限运行）
shell> chown -R mysql .
shell> chgrp -R mysql .

3.（以root权限运行）
shell> apt-get install libaio1 libaio-dev
shell> ./scripts/mysql_install_db --user=mysql

3.The mysql_install_db program creates the server's data directory with mysql as the owner. Under the data directory, it creates directories for the mysql database that holds the grant tables and the test database that you can use to test MySQL.The script also creates privilege table entries for root and anonymous-user accounts. The accounts have no passwords initially.

It is important to make sure that the database directories and files are owned by the mysql login account so that the server has read and write access to them when you run it later. To ensure this if you run mysql_install_db as root, include the --user option as shown. Otherwise, you should execute the script while logged in as mysql, in which case you can omit the --user option from the command.

4.Most of the MySQL installation can be owned by root if you like. The exception is that the data directory must be owned by mysql. To accomplish this, run the following commands as root in the installation directory:

4.（以root权限运行）
shell> chown -R root .
shell> chown -R mysql data

5.暂无

6.If you want MySQL to start automatically when you boot your machine, you can copy support-files/mysql.server to the location where your system has its startup files. More information can be found in the mysql.server script itself, and in Section 2.10.1.2, “Starting and Stopping MySQL Automatically”. 如下：

Generally, you start the mysqld server in one of these ways:

，，Invoke mysqld_safe, which tries to determine the proper options for mysqld and then runs it with those options. This script is used on Unix and Unix-like systems. SeeSection 4.3.2, “mysqld_safe — MySQL Server Startup Script”.

，，Invoke mysql.server. This script is used primarily at system startup and shutdown on systems that use System V-style run directories (that is,/etc/init.d and run-level specific directories), where it usually is installed under the name mysql. The mysql.server script starts the server by invoking mysqld_safe. See Section 4.3.3, “mysql.server — MySQL Server Startup Script”.

[插播4.1 Overview of MySQL Programs]

The MySQL server, mysqld, is the main program that does most of the work in a MySQL installation. The server is accompanied by several related scripts that assist you in starting and stopping the server:

• mysqld

  The SQL daemon (that is, the MySQL server). To use client programs, mysqld must be running, because clients gain access to databases by connecting to the server. See Section 4.3.1, “mysqld — The MySQL Server”.

• mysqld_safe

  A server startup script. mysqld_safe attempts to start mysqld. See Section 4.3.2, “mysqld_safe — MySQL Server Startup Script”.

• mysql.server

  A server startup script. This script is used on systems that use System V-style run directories containing scripts that start system services for particular run levels. It invokes mysqld_safe to start the MySQL server. See Section 4.3.3, “mysql.server — MySQL Server Startup Script”.

• mysqld_multi

  A server startup script that can start or stop multiple servers installed on the system. See Section 4.3.4, “mysqld_multi — Manage Multiple MySQL Servers”.   

MySQL client programs that connect to the MySQL server:

• mysql

  The command-line tool for interactively entering SQL statements or executing them from a file in batch mode. See Section 4.5.1, “mysql — The MySQL Command-Line Tool”.

• mysqladmin

  A client that performs administrative operations, such as creating or dropping databases, reloading the grant tables, flushing tables to disk, and reopening log files. mysqladmin can also be used to retrieve version, process, and status information from the server. See Section 4.5.2, “mysqladmin — Client for Administering a MySQL Server”.

[插播完毕]

To start or stop the server manually using the mysql.server script, invoke it with start or stop arguments:

;以root权限运行
shell> mysql.server start                  
shell> mysql.server stop

Before mysql.server starts the server, it changes location to the MySQL installation directory, and then invokes mysqld_safe.

To start and stop MySQL automatically on your server, you need to add start and stop commands to the appropriate places in your /etc/rc* files. 接着看下文，

If you install MySQL from a source distribution or using a binary distribution format that does not install mysql.server automatically, you can install it manually. The script can be found in the support-files directory under the MySQL installation directory or in a MySQL source tree.

To install mysql.server manually, copy it to the/etc/init.d directory with the name mysql, and then make it executable. Do this by changing location into the appropriate directory where mysql.server is located and executing these commands:

;以root权限运行
shell> cp ./support-files/mysql.server /etc/init.d/mysql
shell> chmod +x /etc/init.d/mysql

After installing the script, the commands needed to activate it to run at system startup depend on your operating system. On Linux, you can use chkconfig（Ubuntu对此不再提供支持，有一个替代的是sysv-rc-conf，见下文）:

shell> chkconfig --add mysql      ;不做此项，请接着看下面

For other systems, consult your operating system documentation to see how to install startup scripts.

sudo apt-get install sysv-rc-conf
cd /etc/init.d
sudo sysv-rc-conf atd on

Ubuntu下已经以sysv-rc-conf替代chkconfig了，执行sysv-rc-conf有图形和命令行两种格式，命令行格式如下：

# sysv-rc-conf --level 35 ssh off
# sysv-rc-conf atd on

The first example will turn ssh off on levels 3 and 5. The second example turns atd on for run levels 2, 3, 4, and 5.

# sysv-rc-conf mysql on
# sysv-rc-conf --list mysql       ;;可查看mysql的执行等级

在进行第七步之前，我们需要在 my.cnf 中设置一下 mysql.server，先来生成一个my.cnf，这里我们使用一个在线生成配置文件的网站，它为你方便地提供了优化了的 my.cnf：[https://tools.percona.com/]yhL#66     关于如何使用配置文件(如my.cnf)，可以查看4.2.6 Using Option Files；而对配置文件中详细选项的了解，For a full description of MySQL Server command options, system variables, and status variables, see Section 5.1, “The MySQL Server”.

[插播，了解一下如何使用Option Files，即配置文件.cnf]4.2.6 Using Option Files

On Unix, Linux and Mac OS X, MySQL programs read startup options from the following files, in the specified order (top items are used first).

File Name	Purpose
/etc/my.cnf	Global options
/etc/mysql/my.cnf	Global options
SYSCONFDIR/my.cnf	Global options
$MYSQL_HOME/my.cnf	Server-specific options
defaults-extra-file	The file specified with --defaults-extra-file=path, if any
~/.my.cnf	User-specific options
~/.mylogin.cnf	Login path options

~ represents the current user's home directory (the value of $HOME).

SYSCONFDIR represents the directory specified with the SYSCONFDIR option to CMake when MySQL was built. By default, this is the etc directory located under the compiled-in installation directory.

MYSQL_HOME is an environment variable containing the path to the directory in which the server-specific my.cnf file resides. If MYSQL_HOME is not set and you start the server using the mysqld_safe program, mysqld_safe attempts to set MYSQL_HOME as follows:

• Let BASEDIR and DATADIR represent the path names of the MySQL base directory and data directory, respectively.

• If there is a my.cnf file in DATADIR but not in BASEDIR, mysqld_safe sets MYSQL_HOME to DATADIR.

• Otherwise, if MYSQL_HOME is not set and there is no my.cnf file in DATADIR, mysqld_safe sets MYSQL_HOME to BASEDIR.

In MySQL 5.6, use of DATADIR as the location for my.cnf is deprecated.摒弃

Typically, DATADIR is /usr/local/mysql/data for a binary installation or /usr/local/var for a source installation. Note that this is the data directory location that was specified at configuration time, not the one specified with the --datadir option when mysqld starts. Use of --datadir at runtime has no effect on where the server looks for option files, because it looks for them before processing any options.

MySQL looks for option files in the order just described and reads any that exist. If an option file that you want to use does not exist, create it with a plain text editor.

If multiple instances of a given option are found, the last instance takes precedence. There is one exception: For mysqld, the first instance of the --user option is used as a security precaution, to prevent a user specified in an option file from being overridden on the command line.

Note

On Unix platforms, MySQL ignores configuration files that are world-writable. This is intentional as a security measure.

Any long option that may be given on the command line when running a MySQL program can be given in an option file as well. To get the list of available options for a program, run it with the --help option.

The syntax for specifying options in an option file is similar to command-line syntax (see Section 4.2.4, “Using Options on the Command Line”). However, in an option file, you omit the leading two dashes from the option name and you specify only one option per line. For example, --quick and --host=localhost on the command line should be specified as quick and host=localhost on separate lines in an option file. To specify an option of the form --loose-opt_name in an option file, write it as loose-opt_name.

If an option group name is the same as a program name, options in the group apply specifically to that program. For example, the [mysqld] and [mysql] groups apply to the mysqld server and the mysql client program, respectively.

The [client] option group is read by all client programs (but not by mysqld). This enables you to specify options that apply to all clients. For example, [client] is the perfect group to use to specify the password that you use to connect to the server. (But make sure that the option file is readable and writable only by yourself, so that other people cannot find out your password.) Be sure not to put an option in the [client] group unless it is recognized by all client programs that you use. Programs that do not understand the option quit after displaying an error message if you try to run them.

[插播完毕]

[插播，了解配置文件中那些单个选项的意义]see Section 5.1, “The MySQL Server”.自己看吧。

回到[https://tools.percona.com/]继续生成my.cnf，其中，data directory设置为/usr/local/mysql/data，我的my.cnf文件：

 设置前，data文件夹里的文件(以备日后查看)：

drwxr-xr-x  5 mysql mysql     4096 Oct  9 08:54 ./
drwxr-xr-x 13 root  mysql     4096 Oct  7 20:16 ../
-rw-rw----  1 mysql mysql       56 Oct  7 21:25 auto.cnf
-rw-rw----  1 mysql mysql 12582912 Oct  9 08:54 ibdata1
-rw-rw----  1 mysql mysql 50331648 Oct  9 08:54 ib_logfile0
-rw-rw----  1 mysql mysql 50331648 Oct  7 20:42 ib_logfile1
drwx------  2 mysql mysql     4096 Oct  7 20:42 mysql/
-rw-r-----  1 mysql mysql    19610 Oct  9 08:54 ovonel-usa.err
-rw-rw----  1 mysql mysql        5 Oct  9 08:54 ovonel-usa.pid
drwx------  2 mysql mysql     4096 Oct  8 10:53 performance_schema/
drwxr-xr-x  2 mysql mysql     4096 Oct  7 16:34 test/

最后网站生成的配置文件如下：

# Generated by Percona Configuration Wizard (http://tools.percona.com/) version REL5-20120208
# Configuration name server-dev-binary-1009 generated for #**********@163.com at 2014-10-09 04:32:10

[mysql]

# CLIENT #
port                           = 3306
socket                         = /usr/local/mysql/data/mysql.sock

[mysqld]

# GENERAL #
user                           = mysql
default-storage-engine         = InnoDB
socket                         = /usr/local/mysql/data/mysql.sock
pid-file                       = /usr/local/mysql/data/mysql.pid

# MyISAM #
key-buffer-size                = 32M
myisam-recover                 = FORCE,BACKUP

# SAFETY #
max-allowed-packet             = 16M
max-connect-errors             = 1000000

# DATA STORAGE #
datadir                        = /usr/local/mysql/data/

# BINARY LOGGING #
log-bin                        = /usr/local/mysql/data/mysql-bin
expire-logs-days               = 14
sync-binlog                    = 1

# CACHES AND LIMITS #
tmp-table-size                 = 32M
max-heap-table-size            = 32M
query-cache-type               = 0
query-cache-size               = 0
max-connections                = 500
thread-cache-size              = 50
open-files-limit               = 65535
table-definition-cache         = 4096
table-open-cache               = 4096

# INNODB #
innodb-flush-method            = O_DIRECT
innodb-log-files-in-group      = 2
innodb-log-file-size           = 64M
innodb-flush-log-at-trx-commit = 1
innodb-file-per-table          = 1
innodb-buffer-pool-size        = 128M

# LOGGING #
log-error                      = /usr/local/mysql/data/mysql-error.log
log-queries-not-using-indexes  = 1
slow-query-log                 = 1
slow-query-log-file            = /usr/local/mysql/data/mysql-slow.log

在6中，If you installed MySQL using a source distribution, you may want to optionally copy one of the provided configuration files from the support-files directory into your /etc directory. There are different sample configuration files for different use cases, server types, and CPU and RAM configurations. If you want to use one of these standard files, you should copy it to /etc/my.cnf, or /etc/mysql/my.cnf and edit and check the configuration before starting your MySQL server for the first time.

这里我将生成的my.cnf复制到/etc/mysql目录下：

$ sudo mkdir /etc/msql
$ pwd
/etc/mysql
$ sudo vi my.cnf             ;;然后将上面的配置文件内容复制粘贴

Section 2.10.1.2, “Starting and Stopping MySQL Automatically”.       You can add options for mysql.server in a global /etc/my.cnf file. A typical /etc/my.cnf file might look like this:   [这里我修改自己对应的/etc/mysql/my.cnf，添加到末尾]

[mysqld]

# GENERAL #
user                                   = mysql
default-storage-engine           = InnoDB
socket                                = /usr/local/mysql/data/mysql.sock
pid-file                               = /usr/local/mysql/data/mysql.pid

;..........................
# LOGGING #
log-error                              = /usr/local/mysql/data/mysql-error.log
log-queries-not-using-indexes   = 1
slow-query-log                      = 1
slow-query-log-file                 = /usr/local/mysql/data/mysql-slow.log

[mysql.server]

# BASE DIRECTORY #
basedir=/usr/local/mysql

The mysql.server script supports the following options: basedir, datadir, and pid-file. If specified, they must be placed in an option file, not on the command line. mysql.server supports only start and stop as command-line arguments.

The following table shows which option groups the server and each startup script read from option files.

Table 2.15 MySQL Startup scripts and supported server option groups

Script	Option Groups
mysqld	[mysqld], [server], [mysqld-major_version]
mysqld_safe	[mysqld], [server], [mysqld_safe]
mysql.server	[mysqld], [mysql.server], [server]

至此，Section 2.10.1.2, “Starting and Stopping MySQL Automatically”. 一节基本上就练习完了。返回2.10.1 Postinstallation Procedures for Unix-like Systems接着做第7步。

7. Start the MySQL Server:

shell> bin/mysqld_safe --user=mysql &          ；；需要以root权限运行

To ensure this if you run mysqld_safe as root, include the --user option as shown.

8. Use mysqladmin to verify that the server is running. The following commands provide simple tests to check whether the server is up and responding to connections:

shell> bin/mysqladmin version
shell> bin/mysqladmin variables

运行结果：

$ ./bin/mysqladmin version
./bin/mysqladmin  Ver 8.42 Distrib 5.6.21, for linux-glibc2.5 on x86_64
Copyright (c) 2000, 2014, 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.

Server version        5.6.21
Protocol version    10
Connection        Localhost via UNIX socket
UNIX socket        /tmp/mysql.sock
Uptime:            2 hours 6 min 27 sec

Threads: 1  Questions: 2  Slow queries: 0  Opens: 67  Flush tables: 1  Open tables: 60  Queries per second avg: 0.000

9. Verify that you can shut down the server:

$ ./bin/mysqladmin -u root shutdown
验证一下是否关闭了
$ ./bin/mysqladmin version
./bin/mysqladmin: connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)'
Check that mysqld is running and that the socket: '/tmp/mysql.sock' exists!
$ ./bin/mysqladmin variables
./bin/mysqladmin: connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)'
Check that mysqld is running and that the socket: '/tmp/mysql.sock' exists! 

 10. Verify that you can start the server again. Do this by using mysqld_safe or by invoking mysqld directly. For example:

$ ./bin/mysqld_safe --user=mysql  &       ；；需要以root权限运行
$ sudo netstat -tap | grep mysql
tcp6       0      0 [::]:mysql              [::]:*                  LISTEN      30506/mysqld

进行验证，

shell> bin/mysqladmin version 
shell> bin/mysqladmin variables

执行之后出错：

./bin/mysqladmin: connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)'
Check that mysqld is running and that the socket: '/tmp/mysql.sock' exists!

解释的原因是不能通过'/tmp/mysql.sock'连接到localhost，执行ls /tmp -l果然没有mysql.sock文件存在。具体解释请看：B.5.2.2 Can't connect to [local] MySQL server。链接中给出的解释：

Someone has removed the Unix socket file that mysqld uses (/tmp/mysql.sock by default). For example, you might have a cron job that removes old files from the /tmp directory. You can always run mysqladmin version to check whether the Unix socket file that mysqladmin is trying to use really exists. The fix in this case is to change the cron job to not remove mysql.sock or to place the socket file somewhere else. See Section B.5.4.5, “How to Protect or Change the MySQL Unix Socket File”. 结合这段分析，我的问题纠正就从这B.5.4.5来做：

The default location for the Unix socket file that the server uses for communication with local clients is /tmp/mysql.sock.

On some versions of Unix, anyone can delete files in the /tmp directory or other similar directories used for temporary files. If the socket file is located in such a directory on your system, this might cause problems.

Another approach is to change the place where the server creates the Unix socket file. If you do this, you should also let client programs know the new location of the file. You can specify the file location in several ways:

(1)Specify the path in a global or local option file. For example, put the following lines in /etc/my.cnf,我的是/etc/mysql/my.cnf:这样，我的my.cnf末尾就成下面这样了：

# Added by yh@2014-10-10 #
[mysql.server]

# BASE DIRECTORY #
basedir=/usr/local/mysql

# GENERAL #
socket=/usr/local/mysql/data/mysql.sock

# Added by yh@2014-10-10 #
[client]

socket=/usr/local/mysql/data/mysql.sock

之后测试成功：

$ sudo ./bin/mysqladmin version

接着做11步，

11. Run some simple tests to verify that you can retrieve information from the server. The output should be similar to what is shown here:

$ ./bin/mysqlshow 
+--------------------+
|     Databases      |
+--------------------+
| information_schema |
| test               |
+--------------------+

以下不做，直接跳过到13步：

13. At this point, you should have the server running. However, none of the initial MySQL accounts have a password, and the server permits permissive access to test databases. To tighten security, follow the instructions in Section 2.10.2, “Securing the Initial MySQL Accounts”.待做完安全设置，再返回2.10.1完成本节剩下的“时区”和“环境变量”设置(点击查看)，先跨过下面两段。

The MySQL 5.6 installation procedure creates time zone tables in the mysql database but does not populate them. To do so, use the instructions in Section 10.6, “MySQL Server Time Zone Support”.

To make it more convenient to invoke programs installed in the bin directory under the installation directory, you can add that directory to your PATH environment variable setting. That enables you to run a program by typing only its name, not its entire path name. See Section 4.2.10, “Setting Environment Variables”.

------------>2.10.2 Securing the Initial MySQL Accounts

The mysql.user grant table defines the initial MySQL user accounts and their access privileges:

root用户：Some accounts have the user name root. These are superuser accounts that have all privileges and can do anything. The initial root account passwords are empty, so anyone can connect to the MySQL server as root without a password and be granted all privileges.

On Unix, each root account permits connections from the local host. Connections can be made by specifying the host name localhost, the IP address 127.0.0.1, the IPv6 address ::1, or the actual host name or IP address.      An attempt to connect to the host 127.0.0.1 normally resolves to the localhost account. However, this fails if the server is run with the --skip-name-resolve option, so the 127.0.0.1 account is useful in that case. The ::1 account is used for IPv6 connections.

匿名用户：Some accounts are for anonymous users. These have an empty user name. The anonymous accounts have no password, so anyone can use them to connect to the MySQL server.

On Unix, each anonymous account permits connections from the local host. Connections can be made by specifying a host name of localhost for one of the accounts, or the actual host name or IP address for the other.

To display which accounts exist in the mysql.user table and check whether their passwords are empty, use the following statement:

；；启动mysqld先
$ sudo netstat -tap | grep mysql               ;;查看是否有mysqld已经存在
$ sudo ./bin/mysqld_safe --user=mysql &
$ sudo ./bin/mysqladmin version                ;;验证一下启动正常不
$ sudo ./bin/mysql                             ;;root权限运行才可
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 3
Server version: 5.6.21-log MySQL Community Server (GPL)

Copyright (c) 2000, 2014, 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> SELECT User, Host, Password FROM mysql.user;

+------+--------------------+----------+
| User | Host               | Password |
+------+--------------------+----------+
| root | localhost          |          |
| root | myhost.example.com |          |
| root | 127.0.0.1          |          |
| root | ::1                |          |
|      | localhost          |          |
|      | myhost.example.com |          |
+------+--------------------+----------+

your MySQL installation is unprotected until you do something about it:

• You should assign a password to each MySQL root account.

• If you want to prevent clients from connecting as anonymous users without a password, you should either assign a password to each anonymous account or else remove the accounts.

Note

For additional information about setting passwords, see Section 6.3.5, “Assigning Account Passwords”. If you forget your root password after setting it, see Section B.5.4.1, “How to Reset the Root Password”.

Assigning root Account Passwords

 The root account passwords can be set several ways. The following discussion demonstrates three methods:

• Use the SET PASSWORD statement

• Use the UPDATE statement

• Use the mysqladmin command-line client program

For Unix, do this:

mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('newpwd');
mysql> UPDATE mysql.user SET Password = PASSWORD('newpwd')
    ->     WHERE User = 'root';
mysql> FLUSH PRIVILEGES;

The FLUSH statement causes the server to reread the grant tables. Without it, the password change remains unnoticed by the server until you restart it.

详细方法请移步:2.10.2 Securing the Initial MySQL Accounts。

Assigning Anonymous Account Passwords

The mysql commands in the following instructions include a -p option based on the assumption that you have set the root account passwords using the preceding instructions and must specify that password when connecting to the server.否则会报错：[与此类似，以后执行mysql, mysqladmin, mysqld_safe 等程序都需带参数-p]

$ sudo ./bin/mysql
[sudo] password for xxxx: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

To assign passwords to the anonymous accounts, connect to the server as root, then use either SET PASSWORD or UPDATE. Be sure to encrypt the password using the PASSWORD() function.

To use SET PASSWORD on Unix, do this:

/usr/local/mysql$ sudo ./bin/mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 5
Server version: 5.6.21-log MySQL Community Server (GPL)

Copyright (c) 2000, 2014, 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> UPDATE mysql.user SET Password = PASSWORD('newpwd')
    ->     WHERE User = '';
Query OK, 2 rows affected (0.06 sec)
Rows matched: 2  Changed: 2  Warnings: 0

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.06 sec)

 详细方法请移步:2.10.2 Securing the Initial MySQL Accounts。

Securing Test Databases

By default, the mysql.db table contains rows that permit access by any user to the test database and other databases with names that start with test_. (These rows have an empty User column value, which for access-checking purposes matches any user name.) This means that such databases can be used even by accounts that otherwise possess no privileges. If you want to remove any-user access to test databases, do so as follows:

sudo ./bin/mysql -u root -p
Enter password: (enter root password here)
mysql> DELETE FROM mysql.db WHERE Db LIKE 'test%';
Query OK, 2 rows affected (0.04 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.06 sec)

With the preceding change, only users who have global database privileges or privileges granted explicitly for the test database can use it.2.10.2 Securing the Initial MySQL Accounts文末说的删除test数据库，我这里不做。

 

[6.1.2.1 End-User Guidelines for Password Security]    

On Unix, the mysql client writes a record of executed statements to a history file (see Section 4.5.1.3, “mysql Logging”). By default, this file is named .mysql_history and is created in your home directory. Passwords can be written as plain text in SQL statements such as CREATE USER, GRANT, and SET PASSWORD, so if you use these statements, they are logged in the history file. To keep this file safe, use a restrictive access mode, the same way as described earlier for the .my.cnf file.

sudo chmod 600 ~/.mysql_history

 

现在是时候返回2.10.1完成上面未完成的事情了（“时区”和“环境变量”设置）

----->2.10.1 Postinstallation Procedures for Unix-like Systems

The MySQL 5.6 installation procedure creates time zone tables in the mysql database but does not populate them. To do so, use the instructions in Section 10.6, “MySQL Server Time Zone Support”.[这留到以后要用到的时候再做]

[环境变量设置]

To make it more convenient to invoke programs installed in the bin directory under the installation directory, you can add that directory to your PATH environment variable setting. That enables you to run a program by typing only its name, not its entire path name. See Section 4.2.10, “Setting Environment Variables”.    [[Section 2.12, “Environment Variables”说，In many cases, it is preferable to use an option file instead of environment variables to modify the behavior of MySQL. See Section 4.2.6, “Using Option Files”. ]]

The commands to set environment variables can be executed at your command prompt to take effect immediately, but the settings persist only until you log out. To have the settings take effect each time you log in, use the interface provided by your system or place the appropriate command or commands in a startup file that your command interpreter reads each time it starts.

On Unix, typical shell startup files are .bashrc or .bash_profile for bash, or .tcshrc for tcsh.

$ echo $SHELL
/bin/bash                             ;;显示我的shell是bash

Suppose that your MySQL programs are installed in /usr/local/mysql/bin and that you want to make it easy to invoke these programs. To do this, set the value of the PATH environment variable to include that directory. For example, if your shell is bash, add the following line to your .bashrc file:

$ vi ~/.bashrc
在文末添加下行：
PATH=${PATH}:/usr/local/mysql/bin

bash uses different startup files for login and nonlogin shells, so you might want to add the setting to .bashrc for login shells and to .bash_profile for nonlogin shells to make sure that PATH is set regardless.

If the appropriate startup file does not exist in your home directory, create it with a text editor. 

更改完成之后，可以在命令行中直接调用mysql程序了，但是一旦加上sudo运行，则提示出错，明明PATH目录下存在该文件的：

$ sudo mysql
sudo： mysql：找不到命令

造成该错误的原因是Linux的限制了sudo执行的范围，这出于安全方面的考虑，怎么做改变呢，参见[http://www.cnblogs.com/yhLinux/articles/4019311.html]，

$ which visudo 
/usr/sbin/visudo
ovonel@ovonel-usa:~$ sudo visudo 
修改之前，visudo是下面这样的：
#
# This file MUST be edited with the 'visudo' command as root.
#
# Please consider adding local content in /etc/sudoers.d/ instead of
# directly modifying this file.
#
# See the man page for details on how to write a sudoers file.
#
Defaults    env_reset
Defaults    secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

# Host alias specification

# User alias specification


修改secure_path，最后是这样的：
# Added by xx@2014-10-11
Defaults    secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/mysql/bin"

附：

1. 设置数据库编码(sudo vi /etc/mysql/my.cnf)：

[client]
default-character-set = utf8

[mysqld]
character-set-server = utf8
collation-server = utf8_general_ci

详细内容见此链接：MySQL设置字符集CHARACTER SET

2. 贴出我的配置文件(PS: vim跨文件操作之全文复制命令"+yG，从当前行复制到文末)：

# Generated by Percona Configuration Wizard (http://tools.percona.com/) version REL5-20120208
# Configuration name server-dev-binary-1009 generated for #**********@163.com at 2014-10-09 04:32:10

[mysql]

# CLIENT #
port                           = 3306
socket                         = /usr/local/mysql/data/mysql.sock

[mysqld]

# GENERAL #
user                           = mysql
default-storage-engine         = InnoDB
socket                         = /usr/local/mysql/data/mysql.sock
pid-file                       = /usr/local/mysql/data/mysql.pid

# MyISAM #
key-buffer-size                = 32M
myisam-recover                 = FORCE,BACKUP

# SAFETY #
max-allowed-packet             = 16M
max-connect-errors             = 1000000

# DATA STORAGE #
datadir                        = /usr/local/mysql/data/

# BINARY LOGGING #
log-bin                        = /usr/local/mysql/data/mysql-bin
expire-logs-days               = 14
sync-binlog                    = 1

# CACHES AND LIMITS #
tmp-table-size                 = 32M
max-heap-table-size            = 32M
query-cache-type               = 0
query-cache-size               = 0
max-connections                = 500
thread-cache-size              = 50
open-files-limit               = 65535
table-definition-cache         = 4096
table-open-cache               = 4096

# INNODB #
innodb-flush-method            = O_DIRECT
innodb-log-files-in-group      = 2
innodb-log-file-size           = 64M
innodb-flush-log-at-trx-commit = 1
innodb-file-per-table          = 1
innodb-buffer-pool-size        = 128M

# LOGGING #
log-error                      = /usr/local/mysql/data/mysql-error.log
log-queries-not-using-indexes  = 1
slow-query-log                 = 1
slow-query-log-file            = /usr/local/mysql/data/mysql-slow.log

# Added by yh @2014-10-19 #
# SET CODING #
character-set-server = utf8
collation-server = utf8_general_ci


# Added by yh@2014-10-10 #
[mysql.server]

# BASE DIRECTORY #
basedir=/usr/local/mysql

# GENERAL #
socket=/usr/local/mysql/data/mysql.sock


# Added by yh@2014-10-10 #
[client]

socket=/usr/local/mysql/data/mysql.sock

# Added by yh@2014-0-19 #
default-character-set = utf8

（完）

 相关链接：

日志文件管理：http://www.cnblogs.com/yhLinux/articles/4029191.html