brightnessctl

 Changing the brightness of the screen of a laptop, you can use the command brightnessctl.
1. brightnessctl -l
2. brightnessctl set 5000

Disable touchpad

To disable touchpad on laptop:

xinput list

xinput disable [number]

What is a mountpoint?

A mount point is a directory on a file system that is logically linked to another file system. Mount points are used to make the data on a different physical storage drive easily available in a folder structure. Mount points are fundamental to Unix, Linux and macOS. Windows can use mount points, but it is not common.

https://www.techtarget.com/whatis/definition/mount-point

 

Tree command

De tree command kan ook als grep werken:
tree humble*

Window managers

Distrotube, A Comprehensive Guide To Tiling Window Managers:

https://youtu.be/Obzf9ppODJU

1. dwm => very minimal. You will have to patch it. Written in C.
2. xmonad => also very minimal. Written in Haskell
3. qtile => looks like dwm and xmond but it is written in Python
4. awesome => perfect for beginners. It looks like Openbox in that you can open programs with rightclicking in the screen.
5. i3 => very easy
6. herbstluftwm => 
7. bspwm => binary space partitioning window manager. You must create your own hotkey file.

Adjusting mouse sensitivity

https://forums.bunsenlabs.org/viewtopic.php?id=1566

 

 

Umount Target is Busy

 # Umount Target is Busy
Lazy unmount: The third and safer alternative to the force unmount is a lazy unmount. A lazy unmount allows the system to detach the specified mount point in a hierarchical manner. It works by removing any references to the filesystem as soon as it’s not busy.

umount -l /path/to/dev

How to view fonts on your system

Use the command fc-list and then grep to find the particular font you want

fc-list | grep liberation

Xrandr, arandr, xprop and xev

Xrandr is used to set the size, orientation and/or reflection of the outputs for a screen. It can also set the screen size. A

ArandR is a visual front end for XRandR 1.2 (per display options), which provides full control over positioning, saving and loading to/from shell scripts and easy integration with other applications. 

The xprop utility is for displaying window and font properties in an X server.  One window or font is selected using the command line  arguments or possibly in the case of a window, by clicking on the desired window. A list of properties is then given, possibly with formatting information. 

 xev - print contents of X events.

Information about packages

Commands to get information about packages:

type -p nmcli

dpkg -S /usr/bin/nmcli

apt-cache depends network-manager

https://askubuntu.com/questions/972596/nmcli-command-not-found-ubuntu-16-04

When you do “apt-get install” where are the .deb files stored?

They're stored in:

/var/cache/apt/archives/

unless you've issued a:

apt-get clean

(https://superuser.com/questions/378686/when-you-do-apt-get-install-where-are-the-deb-files-stored)

Deletion of make install files

Deletion of make install files

https://stackoverflow.com/questions/1439950/whats-the-opposite-of-make-install-i-e-how-do-you-uninstall-a-li

sudo make uninstall

In a Debian based system, instead of (or after*) doing make install you can run sudo checkinstall to make a .deb file that gets automatically installed. You can then remove it using the system package manager (e.g. apt/synaptic/aptitude/dpkg). Checkinstall also supports creating other types of package, e.g. RPM.

SSH Key - Still asking for password and passphrase

Add Identity without Keychain

There may be times in which you don't want the passphrase stored in the keychain, but don't want to have to enter the passphrase over and over again.
You can do that like this:

ssh-add ~/.ssh/id_rsa 

This will ask you for the passphrase, enter it and it will not ask again until you restart.

Add Identity Using Keychain

As @dennis points out in the comments, to persist the passphrase through restarts by storing it in your keychain, you can use the -K option (-k for Ubuntu) when adding the identity like this:

ssh-add -K ~/.ssh/id_rsa

Once again, this will ask you for the passphrase, enter it and this time it will never ask again for this identity.

PATH

You can skip the step of manually loading the library by letting Linux do it for you when you log in automatically.

Run below commands

echo ". $HOME/my_functions.lib" >> ~/.bashrc
echo ". $HOME/my_functions.lib" >> ~/.bash_profile
source ~/.bashrc
source ~/.bash_profile
That's it. You can directly execute your function from the command line without doing anything.

Making multiple directories at once

echo "augustus" "september" "oktober" "november" | xargs -n 1 mkdir

No USB device available in Virtualbox

"Please add your user name to the 'vboxusers' group with this command:

sudo adduser [$USER] vboxusers

After that you must logout and login.
Please check this for more details:

https://help.ubuntu.com/community/VirtualBox/USB"

https://superuser.com/questions/956622/no-usb-devices-available-in-virtualbox

Copying the same file to two locations

Copying the same file to two locations by using the cp command twice still seems logical but let us suppose we have to copy the file to three, five, or even more locations. Here is how a single command can achieve this purpose.

Syntax:

$ echo [destination1] [desctination2] [destiantion3]..... | xargs -n 1 cp [/location/sourcefile]

https://vitux.com/copying-one-file-simultaneously-to-multiple-locations-through-ubuntu-command-line/

How to permanently set $PATH on Linux/Unix?

You need to add it to your ~/.profile or ~/.bashrc file.

export PATH="$PATH:/path/to/dir"
Depending on what you're doing, you also may want to symlink to binaries:

cd /usr/bin
sudo ln -s /path/to/binary binary-name
Note that this will not automatically update your path for the remainder of the session. To do this, you should run:

source ~/.profile
or
source ~/.bashrc

https://stackoverflow.com/questions/14637979/how-to-permanently-set-path-on-linux-unix

Get a list of Open Ports in Linux

ss -lntu

-n, --numeric       don't resolve service names
-l, --listening     display listening sockets
-t, --tcp           display only TCP sockets
-u, --udp           display only UDP sockets

Finding permissions on files

- ls -l is the easiest command.

Another one is:

- stat -c %a / lyndasummaries