许多新版Linux系统默认不带rc.local，需要手动添加服务才可启动
Ubuntu 20.04：
1.添加服务(命令一把梭)
cat > /etc/systemd/system/rc-local.service <<EOF
[Unit]
Description=/etc/rc.local
ConditionPathExists=/etc/rc.local
[Service]
Type=forking
ExecStart=/etc/rc.local start
TimeoutSec=0
StandardOutput=tty
RemainAfterExit=yes
SysVStartPriority=99
[Install]
WantedBy=multi-user.target
EOF
2.添加rc.local 文件(命令一把梭)
cat <<EOF >/etc/rc.local
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
exit 0
EOF
3.添加权限并设置开机自启
chmod +x /etc/rc.local
systemctl enable rc-local
systemctl start rc-local.service
4.检查状态
systemctl status rc-local.service
