foreword

The development board burns the Debian system image. Before writing the QT program, I think about how to make the program run automatically at startup, or load some necessary drivers at startup, and some initialization work.

After consulting some articles, the final experiment is feasible, and I will make a record here.

Proceed as follows:

First, write a script first

Create a new empty file mystart with the following content:

#!/bin/sh


#wifi
startPath1=/opt/8723du.ko

if [ ! -f ${startPath1} ];then
	echo ${startPath1}
	echo "File does not exist !"
else
	sudo insmod ${startPath1}
	echo "Wifi has been loaded !"
fi


#usblp
startPath2=/opt/usblp.ko

if [ ! -f ${startPath2} ];then
	echo ${startPath2}
	echo "File does not exist !"
else
	sudo insmod ${startPath2}
	echo "Usblp has been loaded !"
fi


#chmod lp0
startPath3=/dev/usb

if [ ! -d ${startPath3} ];then
	echo ${startPath3}
	echo "Directory does not exist !"
else
	sudo chmod 777 ${startPath3}/lp0
	echo "Permission has been released !"
fi

The approximate content of the script is:

1. If the file exists, load the WIFI driver.

2. If the file exists, load the USB print driver.

3. If the path exists, set the permission of the printer to mount the file.

2. Put the script in the /etc/init.d/ directory and set the executable permission

3. Add a link

sudo ln -s /etc/init.d/mystart /etc/rc2.d/S99mystart

In this way, the script file we wrote can be automatically run when Linux starts.

It's over, sprinkle flowers~~~

written in the back

When Linux starts, it will run a program called init, and then it will start the subsequent tasks, including user environment, network, module drivers, necessary programs and so on.

The script files are stored in the /etc/init.d/ directory, but the running of these scripts is in order, how to determine it?

1. First, the link file of the script is stored in the /etc/rcn.d directory, and n is divided into 0~6, among which:

directory name	illustrate
rc0.d	run when the machine is off
rc1.d	Single-user mode, similar to Windows' safe mode
rc2.d	Multi-user mode, but without NFS support
rc3.d	Full multi-user mode, which is the standard runlevel
rc4.d	Generally not used
rc5.d	Enter X Windows and execute
rc6.d	run when the machine restarts

2. In the rcn.d directory, the naming of the files determines the execution sequence.

For example, in the file S99mystart , S stands for start, and 99 stands for the startup sequence.