rc.local(ubuntu18.04)

系统自带服务/lib/systemd/system/rc-local.service

软连接为 /lib/systemd/system/rc.local.service -> rc-local.service

#  SPDX-License-Identifier: LGPL-2.1+
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

# This unit gets pulled automatically into multi-user.target by
# systemd-rc-local-generator if /etc/rc.local is executable.
[Unit]
Description=/etc/rc.local Compatibility
Documentation=man:systemd-rc-local-generator()
ConditionFileIsExecutable=/etc/rc.local
After=network.target

[Service]
Type=forking
ExecStart=/etc/rc.local start
TimeoutSec=
RemainAfterExit=yes
GuessMainPID=no

可以看到此文件缺少[install]部分，为他加上。

[Install]
WantedBy=multi-user.target

输入systemctl enable rc-local.service

系统启动时将执行/etc/rc.local文件里的内容

16.10开始不再有/etc/rc.local文件

创建

printf '%s\n' '#!/bin/bash' 'exit 0' | sudo tee -a /etc/rc.local

vim /etc/rc.local

添加以下内容用于测试

#!/bin/bash 

touch /var/lock/subsys/local

source /etc/profile

echo `date`,"ok" >>/tmp/test-rc-local.log

sudo chmod +x /etc/rc.local

重启后看效果