Terminal & Common Commands

• Video Tutorial

Opening Terminal in Desktop System

The Terminal dates back to the early days of computing, when there were no visual desktops and many computer operations were performed through terminal commands. Even today, we use terminals in many scenarios and for debugging. Mastering common Linux terminal commands can make your development work much more efficient. (The non-desktop system only displays this terminal after booting.)

Click the third item "Terminal" in the Launch Bar to open the terminal. Items are: Browser, File Manager, Terminal

The first thing you see in the terminal is the prompt, waiting for your instructions. The prompt appears as follows:

pi@WalnutPi:~$

pi indicates the username;

@ followed by WalnutPi indicates the hostname;

~ indicates the current directory;

$ indicates a non-privileged user.

Let's do a simple terminal test. Enter ls in the terminal and press Enter. You will see a listing of files and folder names in the current directory (the non-desktop system has no files in the pi directory by default):

ls

Enter cd Desktop and press Enter. You will see the prompt change, indicating the current directory is now Desktop.

cd Desktop

Opening Terminal via Debug Serial Port

Connect to the computer using a USB-to-TTL adapter via the serial terminal header pins reserved on the WalnutPi, then log in using terminal software such as PuTTY:

Note

When the system fails to boot normally, you can use this feature to observe boot messages. Note that TX and RX are cross-wired, and USB TTL tools with voltage switching functionality must be set to 3.3V.

Note

If you are using a ZeroW, you can connect via the expansion board's debug serial port, or modify the config.txt file to change the debug serial port number, enabling terminal output via uart2 on the 40-pin header. config.txt Debug Serial Port Settings Tutorial

In Device Manager, you can see the device's COM port number:

Open PuTTY:

Enter the COM port number you found for your computer, set the baud rate to 115200, and click Open:

Then a username and password prompt will appear. Enter "pi" for both the regular user account and password. If nothing appears, try pressing the Enter key. After successful login, the WalnutPi terminal information will be displayed.

User Switching

The WalnutPi system has 2 preset users:

• Regular Account (default for desktop system) Username: pi Password: pi
• Administrator Username: root Password: root

Some terminal commands require administrator privileges to execute. You can run them using sudo + command in the terminal. To directly switch to the administrator account in the terminal, use the su command.

Switch to administrator: Enter su in the terminal, press Enter, and then at the Password: prompt enter the password root (the password is not displayed, mind the case). Press Enter again, and the current terminal session will switch to the administrator user.

su

Switch to regular user: Enter su followed by the username and press Enter. For example, to switch to the pi user, enter:

su pi

Common Linux Commands

No.	Command	Full Name	Function
1	ls	list	List files in the current directory
2	pwd	print working directory	Output current directory
3	cd	change directory	Change directory
4	mkdir	make directory	Create a new directory
5	cat	concatenate	Display or concatenate file contents
6	rm	remove	Delete files
7	rmdir	remove directory	Delete directories
8	mv	move	Move/rename files or directories
9	cp	copy	Copy files or directories
10	echo		Display input content in terminal
11	date		Read system date and time
12	grep	global search regular expression and print	Search regular expressions comprehensively and print
13	man	manual	Display command manual
14	sudo	super user do	Execute with root privileges
15	chmod	change mode	Change file read/write permissions
16	./program		Run the program
17	apt	advance package tool	Install/remove software packages
18	exit		Exit
19	reboot		Restart
20	poweroff		Shutdown