bin/mysqld –initialize –user=mysql –basedir=/usr/local/mysql –datadir=/usr/local/mysql/data –log-error=/usr/local/mysql/logs/log.err
–defaults-file=file_name
http://dev.mysql.com/doc/refman/5.7/en/server-options.html
http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
http://dev.mysql.com/doc/refman/5.7/en/option-files.html
http://dev.mysql.com/doc/refman/5.7/en/data-directory-initialization-mysqld.html
##mysqld-safe启动脚本说明(MySQL Server Startup Script)
推荐使用mysqld-safe来启动mysqld服务，它增加了一些安全特性，如重启服务发生错误时会写入日志文件，运行时错误信息写入等
mysqld_safe会尝试启动一个名称叫mysqld的可执行程序，如果想指定一个特定的程序名称，使用–mysqld 或 –mysqld-version选项。还可以用–ledir选项指定在哪个目录搜索mysqld程序
mysqld_safe的许多选项配置是和mysqld一样的,如果指定了一个mysqld_safe不存在的参数，将传递给mysqld，但是如果在配置文件中指定了mysqld_safe组选项，将忽略
mysqld_safe会从配置文件中读取mysqld,server,mysqld_safe等项的配置内容
如你在配置文件中指定了如下信息
[mysqld]
log-error=error.log
mysqld_safe会找到它并用–log-error初始化它
mysqld_safe接受命令行参数配置和配置文件参数配置
如果使用 –defaults-file or –defaults-extra-file配置文件，则参数必需在第一个
mysqld_safe --defaults-file=file_name --port=port_num
mysqld_safe启动要满足下面2个条件中的任意一个
1.mysqld服务程序,data目录可以在相对于工作目录(调用mysqld_safe的目录)目录下找到。
如果是二进制安装，mysqld_safe会搜索bin,data目录下的内容
如果是源码编译安装，mysqld_safe会搜索libexec和var目录下的内容
2.如果工作目录(调用mysqld_safe的目录)下没有mysqld,data程序，它会尝试调用绝对路径，通常是/usr/local/libexec and /usr/local/var目录，如果在配置时指定了相应的目录，应该是以配置的为准。
所以可以在mysql的安装目录(可以是任何位置,如/usr/local/mysql)用以下命令启动mysqld
shell> cd mysql_installation_directory
shell> bin/mysqld_safe &
如果启动失败，可以用 –ledir 和 –datadir 选项指定mysqld服务所在位置，和数据文件目录位置
可以用以下配置，设置mysql错误日志文件位置
–log-error=file_name 写入错误信息到相应的位置,默认是在data目录下的host_name.err文件
–syslog 同时写入错误信息到syslog
–skip-syslog 不写入错误信息到syslog
默认使用–skip-syslog
以下是mysqld_safe接受的命令行参数和配置文件参数。更多的配置文件参数，请参数配置文件说明
Table 5.1 mysqld_safe Options
FormatDescriptionIntroduced
–basedirPath to MySQL installation directory
–core-file-sizeSize of core file that mysqld should be able to create
–datadirPath to data directory
–defaults-extra-fileRead named option file in addition to usual option files
–defaults-fileRead only named option file
–helpDisplay help message and exit
–ledirPath to directory where server is located
–log-errorWrite error log to named file
–malloc-libAlternative malloc library to use for mysqld
–mysqldName of server program to start (in ledir directory)
–mysqld-safe-log-timestampsTimestamp format for logging5.7.11
–mysqld-versionSuffix for server program name
–niceUse nice program to set server scheduling priority
–no-defaultsRead no option files
–open-files-limitNumber of files that mysqld should be able to open
–pid-filePath name of process ID file
–plugin-dirDirectory where plugins are installed
–portPort number on which to listen for TCP/IP connections
–skip-kill-mysqldDo not try to kill stray mysqld processes
–skip-syslogDo not write error messages to syslog; use error log file
–socketSocket file on which to listen for Unix socket connections
–syslogWrite error messages to syslog
–syslog-tagTag suffix for messages written to syslog
–timezoneSet TZ time zone environment variable to named value
–userRun mysqld as user having name user_name or numeric user ID user_id参考http://dev.mysql.com/doc/refman/5.7/en/mysqld-safe.html
