一 启动、停止、重启服务
启动httpd服务：sy
stemctl start httpd.service
停止httpd服务：
systemctl stop httpd.service
重启httpd服务：
systemctl restart httpd.service
运行态重启httpd服务：
systemctl condrestart httpd.service
重新加载httpd服务配置文件：systemctl reload httpd.service
二 查看、禁止、启动服务
开机启动httpd服务：
systemctl enable httpd.service
开机禁止httpd服务：
systemctl disable httpd.service
查看httpd服务状态：
systemctl status
httpd.service
三 systemd命令和sysvinit命令对比
| sysvinit命令 | systemd命令 | 备注 |
| service httpd start | systemctl start httpd.service | 启动httpd服务 |
| service httpd stop | systemctl stop httpd.service | 关闭httpd服务 |
| service httpd restart | systemctl restart httpd.service | 重启httpd服务，而不管httpd服务的当前状态是什么 |
| service httpd reload | systemctl reload httpd.service | 重新载入httpd配置信息而不中断服务 |
| service httpd condrestart | systemctl condrestart httpd.service | 重启httpd服务，如果已在运行，则重启httpd服务，如果没有运行，则无法启动这个服务 |
| service httpd status | systemctl statushttpd.service | 查看httpd服务的运行状态 |
| chkconfig httpdon | systemctl enable httpd.service | 设置httpd服务开机自动开启 |
| chkconfig httpdoff | systemctl disable httpd.service | 禁止httpd服务开机自动开启 |
| chkconfig httpd | systemctl is-enable httpd.service | 检查httpd服务在当前环境下是启动还是禁用的 |
| chkconfig --list | systemctl list-unit-files --type=service | 输出在各个运行级别下所有服务启动还是禁用情况 |
| chkconfig httpd --list | ls /etc/systemd/system/*.wants/httpd.service | 查看httpd服务在各个运行级别下的启用和禁用情况 |
四 systemd电源管理命令
| systemctl命令 | 含义 |
| systemctl poweroff | 关闭系统 |
| systemctl reboot | 重启系统 |
| systemctl suspend | 进入待机模式 |
| systemctl hibernate | 进入休眠模式 |
| systemctl hybrid-sleep | 进入混合休眠模式 |
