When you first get in touch with the Linux world as a Windows user, the frustration usually does not wait long.

Especially working with the console is unfamiliar and almost impossible without knowing the right commands. Also, the file system or folder structure differs greatly from Windows.

In order to facilitate the entry into the Linux world, I have tried to summarize the most important information, functions and commands.

Hints for our lovely english readers: Basically, many of the articles on Nerdiy.de are translations from the original german articles. Therefore, it may happen here and there that some illustrations are not available in english and that some translations are weird/strange/full of mistakes or generally totaly wrong. So if you find some obvious (or also not obvious) mistakes don't hesitate to leave us a hint about that in the comment section.
Also please don't get confused, that instead of a "dot" often a "comma" is used as decimal separator. 🙂

Safety instructions

I know the following hints are always a bit annoying and seem unnecessary. But unfortunately, many people who knew it "better" from carelessness lost their eyes, fingers or other things or hurt themselves. In comparison, a loss of data is almost not worth mentioning, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Even the coolest project is worth no injury or other annoyance. https://www.nerdiy.de/en/sicherheitshinweise/

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Requirements

Helpful Articles:
To learn how to rightly find yourself in the Linux world, it's best to deal with it directly. “Learning by doing” so to speak. Don't be afraid to break something. The worst thing that could happen is that you have to reinstall Raspian.

How to do that and how you generally configured a working RaspberryPI I described in the following articles:
RaspberryPi – Setting up for nerdys
RaspberryPI – The First Configuration
RaspberryPi - Control the RaspberryPi via SSH

Required tools:
-none-

Required material:

In the following list you will find all the parts you need to implement this article.

Commands in the console

The console under Linux is twofold. On the one hand, you can use it to navigate through the folder structure of the Rasp Pi and thus change the respective directory in which you are currently "located".
I (and possibly others too) call this directory working directory, because it is always the directory in which the currently running commands are executed and access files.
For example, if you create a folder, it will be created in the current working directory (without further details).
Paths are either (relatively) given from the working directory or absolutely from the root directory (ie the highest folder level).

On the other hand, the console is also command prompt. So commands can be entered and executed in it.
Finally, it is the commands that allow you to navigate through the folder structure.

The form of the entered commands is almost always the same.

Usually it is:
COMMANDNAME -PARAMATER PATH

This means that a command always consists of the command name, any parameters and, if necessary, path information.

Parameters are different letters that influence the behavior of the command. These are different for each command. A complete list of parameters and general help can be found for each command by specifying the command name and the –help parameter.

Example:

cp --help

(Note that you must enter two dashes before the "help")

Take a look at all possible parameters and a few examples of the "cp" command.

So if you forget how a command works or forget a parameter you have an integrated documentation at hand here.

Working in the console

Last entered command display

Arrow keys up/down

By pressing the up arrow key you can see your last command entered.

If you want to execute a selected one again, just press the Enter key.

If you want to edit it again, you can use the arrow keys to navigate left and right through the command.

Delete terminal output

clear

This command clears the current console session and displays a "fresh" prompt.

Complete the path entries

The tab key automatically completes path information.

For example, if you just want to switch from the current folder to the next folder named "NextFolderWithFastFamilyLongName", just type the following command:

cp Next

and then press the tab key.

Linux then completes "next" automatically to "NextFolderWithFastlyLongName".

If, in addition to the folder "NextFolderWithFastlyLongName" it also happens to have a similar sounding folder (eg "nextfolderwithshortname") in the current directory, the folder name will only be completed as far as the two folder names are different. In this case only until "nextfolderwith". However, if you then enter a letter of the desired folder, the completion can be performed again.

For example, typing "nextfolderfolderwithf" and then pressing the tab key will tell Linux that the folder "NextfolderWithFastlyLongName" must be meant and completes the name accordingly.

So you save a lot of typing. This path completion works in nearly every command.

Stop executing commands

The key combination CTRL+C can be used to terminate currently running processes.

File and folder operations

Show current path

pwd

This command shows you the current absolute (ie complete, outgoing root) path to the directory you are currently in.

Display directory tree

tree

This command displays the folder structure in the current directory.

As the name (tree = tree) suggests, the current folder structure is shown starting from the working directory. That is, the subfolders in folders are represented as the branches of a tree starting from the root. This is easiest to understand by just trying it out. 🙂

List folder contents

ls -la

This command shows you the complete contents of the current directory (including hidden files). But in most cases, a simple:

ls

Createfolder

mkdir new folder

This command creates a new folder in the current directory with the given name (in this case "newfolder").

Delete folder (including content)

rm -R new folder

This command deletes the specified folder (in this case, "new folder") and all files contained in it without asking or warning again.

Delete file

rm fileToBeDeleted

This command deletes the specified file (in this case, the file to be deleted). in the current directory.

Change folder

cd /home/pi

This command changes the directory to the specified directory.

CD ..

With this command you change to the next higher folder level.

This can also be linked. For example, if you want to go up a folder level from the current folder and go directly to another folder, you can do this with the following command:

cd ../newfolderInTheNextMainFolder

With the following command you can switch directly to your home directory:

CD ~

Copy files

cp "filename" "destination"

This command copies the file "filename" to "destination". In this way you can also rename files directly.

cp coolTexttfile.txt stillCoolerTextfile.txt

For example, this will cause the "coolTextfile.txt" to be copied to the current folder again. The copied file will be called "evenMoreCoolerTextfile.txt".

Of course, path information can also be incorporated into the copying processes.

For example, the following command copies the file "coolTextfile.txt" into the subfolder "coolFolder".

cp coolTexttfile.txt coolFolder/coolTexttfile.txt

Move multiple files or a file to another folder

mv -t destination folder file1 file2 file3

Rename file

mv currentfilename desiredfilename

This command is actually a file move (mv = move). Since you can also specify a new name when moving files, this command is also perfect for renaming files.

Download file

wget internetaddress

This command allows you to download files to the current directory.

For this, only the link to the file you want to download behind "wget" must be specified.

Unzip zip file with password

unzip -P PASSWORD 'zipFile.zip'

This command unpacks the password-protected file "zipFile.zip" with the password "PASSWORD" in the current directory. If you want to know what Zip files are, I described this in this article:

Extract rar file with password

unrar e -p PASSWORD 'rarFile.rar'

This command unpacks the password-protected file "rarFile.zip" with the password "PASSWORD" into the current directory. If you want to know what Rar files are, I described this in this article:

Unzip zip file to destination folder

unzip zipfile.zip -d TARGET

This command unpacks the "zipFile.zip" file into the directory specified with DESTINATION.

Pack folder into zip file

zip -r filename.zip FOLDER NAME

Secure deletion of data

shred -fuz for fileToShredForever

This command not only deletes files, it also overwrites the space of the deleted file. As a result, the deleted files cannot be recovered even by forensic means. The command works with the Gutmann method.

Installation of and working with packages

Update program packages

sudo apt-get update && sudo apt-get upgrade

These are actually two commands that are linked by the "&&".

The "&&" in this case means that first the first command and then the second command is executed.

sudo apt-get update

… updates the package list of the “Advanced Packaging Tool” (apt). This tool manages different software packages. Updating the package list therefore downloads the current table of contents of the available software packages.

sudo apt-get upgrade

… then compares the packages already installed on your system with the packages available in the table of contents. If one of the available packages is newer than the package installed on your system, it automatically installs the new version of the package

Install programs/packages

sudo apt-get install PACKETNAME

This command uses the "Advanced Packaging Tool" to install the package specified with "PACKETNAME" and all other necessary packages needed to run this package.

Delete unnecessary programs/packages

sudo apt-get autoremove PACKETNAME

This command is also part of the "Advanced Packaging Tool" and can be executed with and without package name. Without a package name, ie "sudo apt-get autoremove", this command uninstalls all packages that are no longer used because they were only installed as a prerequisite for another package that no longer exists.
Package name, for example "sudo apt-get autoremove RANDOM_PACKET_NAME" uninstalls the specified package and all prerequisites installed during the installation of this package.

RaspberryPi specific commands

Update firmware and kernel of the Rasp Pi

sudo rpi update

This command updates the kernel and important system files of the Rasp Pi. According to the motto "Never touch a running system", this should only be done if important security updates are available or something is not working as it should.

Restart Rasp Pi

sudo reboot

This command safely shuts down the Rasp Pi and restarts it directly. This is perfect for testing if installed software starts automatically after a reboot.

Shut down Rasp Pi safely and immediately

sudo shutdown -h -P now

or the abbreviation (specific for the RaspberryPi)

sudo power off

After running the shutdown command, wait a few more seconds. Just as with Windows systems, it takes a moment for the system to complete all programs/processes. At the same time all possible writing processes are terminated.

This is also the reason why you should always shut down the Rasp Pi properly. If this is currently saving a file to a memory and is then disconnected from the power, the storage process is interrupted. This leads to the fact that any partially written files cannot be read anymore.

If this file happens to be an important file for the system, the Rasp Pi may not start correctly the next time.

If the Rasp Pi is completely shut down you will recognize that the green LED is no longer blinking and only the red LED is lit.

If you should still pull the plug without having shut down the Rasp Pi before you do not need to burst into tears immediately: Mostly it's fine, but just mostly. 🙂

Execute commands as root

sudo

sudo = Super User Do

This command can be set before any command and causes this command to execute as if the superUser "root" were executing it. For example, as a normal user, you could execute commands that would be used to access files that you, as a normal user, do not actually have access to.

To be able to use sudo you have to be entitled to do so. This is determined in the file /etc/sudoers.

Log off from the console

logout

This command terminates the connection to the Rasp Pi and closes the console.

Show Raspberry Pi CPU temperature

echo $ ((`cat/sys/class/thermal/thermal_zone0/temp`/1000))

This command gives you the current temperature of the CPU.

Show Rasp Pi GPU temperature

/opt/vc/bin/vcgencmd measure_temp | cut -c6-9

This command gives you the current temperature of the GPU.

network

IP address or network configuration Display
ifconfig

This command displays information about your network connection. So you can also check which IP address your Rasp Pi has.

List open ports and existing network connections
netstat -tcp -listening -programs -numeric

This command displays all currently open ports and network connections as well as various information about them

Network

Display IP address or network configuration

ifconfig

This command shows you information about your network connection. You can also check which IP address your Rasp Pi has.

List open ports and existing network connections

netstat --tcp --listening --programs --numeric

This command shows you all currently open ports and network connections as well as various information about them

Miscellaneous

Change the password of a user

passwd userName

This command allows you to change the password of the user specified as "userName". In addition, various change and lock intervals can be defined.

Show free space

df -h

This command shows you how much space is still available on your disks.

List all installed USB devices

lsusb

This command gives you all currently installed USB devices.

Show all partitions

sudo blkid

This command gives you all currently installed partitions.

Show detailed information

sudo fdisk -l

With this command you can get detailed information about your partitions.

Force validation of the file system

sudo shutdown -rF now

The file system of the RasPI is normally only checked after every 30th restart. With this command you enforce an immediate check and (if necessary) repair of the file system.

Show Serial by ID

ls -l /dev/serial/by-id

This command displays the ID's of any existing USB to serial adapters. So you can connect serial ports instead of using eg / dev / ttyUSB0 address directly via the ID of the USB device.

This has the advantage that the access via the ID is always unique and the ID does not change even after a restart of the Rasp Pi. If you only access a USB-to-serial adapter via /dev/ttyUSB0, it may happen that it can no longer be reached under /dev/ttyUSB0 after a restart, but maybe under /dev/ttyUSB1.

To avoid this problem, it is advisable to address the serial interface via the ID of the USB serial adapter.

Show all serial ports

ls/dev/tty* or dmesg | grep tty

This command will show you all possible serial ports of the system.

Check other computers for presence in the network

ping *network address*

Use the ping command to check for the presence of other network participants.

This can be a computer on the local network but also on the Internet.

"Network address" is replaced by the IP address or the domain name of the computer whose presence you want to check.

Show running processes

ps

The command "ps" shows you all currently running processes including the ID and a few other information such as utilization, etc.

Termination of a process identified by the process ID

kill processid

This command terminates the process with the process ID "processID".

Output of processor utilization

Top

This command will show you the current utilization of the CPU.

Specify the runtime and load of the computer

up time

By "uptime" you can see the time that has passed since the launch of the RaspI.

Show current user

wer bin ich

This command displays the name of the currently logged-in user.

View the location of a program

which ls

This command displays the location of the parametered program (in this case) "ls".

Folder Structure – Which folder contains which files?

Under Linux, the folder structure is slightly different than in Windows but still logical. If you break down the abbreviations, the rest is almost self-explanatory.

"bin" = binaries: executable files so programs

"sbin" = system binaries: executable system files ie system programs

These two folders contain only files that are important for the system.

User-installed programs are written in /usr/bin other /usr/sbin.

The files in these folders may also be executed by normal users.

The in "am" other "sbin", however, mostly only by users with administrator rights.

"boat": contains important files for booting.

"dev" = devices: This folder contains all device files. These can be used to address different hardware interfaces. For example, USB and serial interfaces.

"lib" = libraries: Contains important libraries that are necessary for some programs.

"lost + found": If files or file fragments are found during the repair of a data carrier, they are moved or saved to this folder.

"mnt" = mount: Contains all temporarily mounted (= mounted) data carriers such as USB sticks.

"opt" = optional: Contains all manually installed programs that require their own libraries.

"proc" = processes: Contains interfaces to the loaded kernel and its procedures.

"root" = root: This is the user directory of the super-user root. It is the only user directory that is not in the home directory.

home: This is the default user folder where every user automatically gets a subfolder. User files can then be stored in this folder. Each user may create files or folders in their own home folder.

"Etc" = et cetera: Default memory location for system-wide configuration files.

Examples and explanations

I find the page tldr.ostera.io very practical

Here you can enter the command you want to use in a search mask and you will automatically be shown further explanations and examples.

I hope this information helps you to make the first entry into the Linux/RaspberryPI world a little easier. If you do not have or you have other criticisms or questions please let me know. You can simply use the comment function under the article. 🙂

Have fun with the project

I hope everything worked as described. If not or you have any other questions or suggestions, please let me know in the comments. Also, ideas for new projects are always welcome. 🙂

P.S. Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you appreciate that I share this information with you, I would be happy about a small donation to the coffee box. 🙂