Linux命令- systemctl

systemctl命令是系统服务管理器指令，它实际上将 service 和 chkconfig 这两个命令组合到一起。

任务	旧指令	新指令
使某服务自动启动	chkconfig --level 3 httpd on	systemctl enable httpd.service
使某服务不自动启动	chkconfig --level 3 httpd off	systemctl disable httpd.service
检查服务状态	service httpd status	systemctl status httpd.service（服务详细信息） systemctl is-active httpd.service （仅显示是否 Active)
显示所有已启动的服务	chkconfig --list	systemctl list-units --type=service
启动某服务	service httpd start	systemctl start httpd.service
停止某服务	service httpd stop	systemctl stop httpd.service
重启某服务	service httpd restart	systemctl restart httpd.service

例子：以nginx为例。
1.启动服务
systemctl start nginx.service

2.设为开机启动
systemctl enable nginx.service

3.停止开机启动
systemctl disable nginx.service

4.查看服务当前状态
systemctl status nginx.service

5.重启服务
systemctl restart nginx.service

6.停止服务
systemctl stop nginx.service


7.查看说有已启动服务
systemctl list -units --type=service

8.开启防火墙22端口
iptables -I INPUT -p tcp --dport 22 -j accept如果还有问题滚逼SELinux 修改/etc/selinux/config SELINUX=”disabled”

9.彻底关闭防火墙
sudo firewall-cmd --state  //查看服务状态
sudo systemctl stop firewalld.service       //停止防火墙
sudo systemctl disable firewalld.service //停止开机启动