Why can't I start my mysql with service mysqld start

I use
/ usr/local/mysql/bin/mysqld-- defaults-file=/etc/my.cnf-- basedir=/usr/local/mysql-- datadir=/mysql/data-- pid-file=/mysql/data/mysql.pid-- socket=/mysql/data/mysql.sock

can be started. Why?

Mar.23,2021

you should take a look at / etc/init.d/ below what is the name of the mysql-related script

ls -al /etc/init.d/mysql*

in many systems, the name of the service script is mysql , rather than mysqld
, so you need to use

to start the service.
service mysql start

it seems that your mysql is not included in the system. If it is compiled and installed, you must first install the service script.

in addition, systemctl is recommended to start the service under the new centos and ubuntu:

systemctl start mysql
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