To Display All Info about your Linux Machine:
uname -a

To change password: passwd

To change password as root for another user:
passwd <username>

To login as a different user:
sudo -iu <username>

To Display current kernel and other installed kernels:
mhwd-kernel -li

To quickly display files/directories:
ls

To display files/directories/hidden files in human readable format:
ls -lah

To Display disk usage of a particular directory:
du -c /directory (displays total disk usage)
du -h /directory (displays total disk usage by file/subdirectory in human readable format)
du -hc /directory (displays total disk usage and usage by file/subdirectory in human readable format)

To compress/archive and encrypt a file:

tar czf <compressed_file_name> <file_tobecompressed_name>

gpg -c <compressed_file_name>

Enter passphrase, and repeat it.

To decompress said file:
gpg -d <compressed_file_name>

tar xzf <decompressed_file_name> <file_tobedecompressed_name>

To compress/archive and encrypt a directory:

tar cvzf = folder | gpg -c --passphrase yourpassword > folder.tar.gz.gpg

And decompress directory:

gpg -d folder.tar.gz.gpg | tar -xvzf -

To decrypt a gpg file and then take it's out put and copy it into the clipboard using xclip:
gpg -d secret_file.gpg | cat | xclip -sel clip

To mount a usb drive via terminal:
cd /mnt
mkdir media
mkdir media/usb-drive

mount /dev/sda1 media/usb-drive

And to unmount the usb drive:

umount media/usb-drive

(make sure to clear your history afterwards)
history -c

To display the differences between two different text files:

grep -f file1.txt file2.txt

To Display top five directories that use the most disk space:
du -ahx . | sort -rh | head -5

To Display location of binary file of program:
whereis <program_name>

To show all available network connections:
nmcli

To show all available network connections in human readable format:
nmcli connection

To connect to wifi network:
nmcli device wifi connect <NETWORK NAME>

To Display ip address info:
ip addr show
inxi -i
curl ifconfig.me
ip neigh

To connect via Network Manager Command Line Interface (nmcli):
nmcli device wifi connect "$SSID" password "$PASSWORD"
nmcli --ask device wifi connect "$SSID" (connects with a prompt that hides password)

To display and change wifi settings;
nmcli

To Display Proccesses:
btop
htop
top
nvtop

To Kill all processes on a specific port:
fuser -k 3000/tcp

To Display HD Storage:
df 

More info about nmcli:
man nmcli (very extensive)
man nmcli-examples(good manual for how to connect and configure network and wifi connections)

To Display CPU and Network info:
inxi -p (shows your partitioning)
inxi -r (shows your repo list)
inxi -i (shows your network details, including public ip)
nmcli -p device (displays in human readable format the available network connections)
nmcli device wifi list (displays with a mini gui the list of available wifi networks)
inxi -w (shows the weather)
lscpu OR
hwinfo --cpu (much more detailed info) OR
inxi -C (sort of like htop with lscpu)

To Display Nvidia GPU info:
nvidia-smi

To display socket statistics:
ss

To display the history of last logged in users:
last

To display your previous commands:
history

To find a specific command in history:
history | grep <command>

Then from there you should be able to use that command using the id number returned:
!365

To clear your history:
history -c

To display your current external/public IP address:
curl ifconfig.me

To display all directories/files:
tree

To display stocks:
mop

To display weather:
inxi -w

To open terminal video player:
mplayer <video_name>

To download youtube videos:
youtube-dl <youtube url>
Only Audio
youtube-dl -x --audio-format mp3 <youtube url>

To display quality versions to download:
youtube-dl -F <youtube url>
And then choose one
youtube-dl -f <choice> <youtube url>

To display all directories EXCEPT for one directory:
tree -I ignored_directory_name
Example:
tree -I node_modules

To display files/directories and their memory usage:
pstree

To Search for all files with the name <query> -i flag means case insensitive:
locate -i <query>

Similar to locate, but within working directory:
find /dir_name/filename.txt

To remove a file:
rm filename

To remove an empty directory:
rm -d directoryname

To remove a directory with files in it:
sudo rm -r directoryname

To remove all files within the current directory that start with a particular prefix:

find . -name 'prefix*' -exec rm {} \;

To securely delete a file (keep in mind this is not perfect, the only way to securely delete files is to physically destroy the hardware):
shred -u -z filename

To kill all processes on port 3000:
fuser -k -n tcp 3000

Grep Command Searches for particular strings/regex patterns within a text file:
Most Basic Use:
grep -F -i <query> <file.txt>

Example:
grep -F -i "tHe" linux_notes.txt

Curl is a powerful CLI command that can GET/POST/PATCH/DELETE/etc. from HTTP/FTP/etc:
curl "https://www.mywebsite.com"

To write curl output to a file:
curl -o "https://www.mywebsite.com" mywebsiteoutput.txt

To format the returned text from curl, use prettier:
prettier mywebsiteoutput.txt

And to save/overwrite the file:
prettier --write mywebsiteoutput.txt

To make a POST request in json format to a database:

curl -X POST http://localhost:3000/maria_database -d '{"id": 1, "task": "do something"}'

To Benchmark GPU:
cd into Unigine_Valley-1.0 (see Uningine for Linux website for download)
./valley (to run benchmark)

To Display system statistics including program resource usage:
ncdu

To enable Uncomplicated Firewall:
sudo ufw enable

To turn off bluetooth:
sudo bluetooth off

To install protonvpn:
Utilize both Manjaro as well as ProtonVPN instructions, make sure
to also install all packages that require pip

To initialize protonvpn:
sudo protonvpn init
sudo protonvpn config
choose 1
enter openvpn login credentials found at protonvpn dashboard
sudo protonvpn connect -f

To disconnect protonvpn:
sudo protonvpn d


To Display Temps:
sensors OR
vcgencmd measure_temp (only works on Raspberry Pi) OR
watch -n 2 vcgencmd measure_temp (to see it adjust every 2 seconds)

To Display NVidia Temps:
nvidia-settings -q GPUCoreTemp -t OR
watch -n1 nvidia-smi (displays updated GPU temp and other stats every sec)

To Display CPU Clock Speed:
vcgencmd measure_clock arm (only works on Raspberry Pi) OR
watch -n 2 vcgencmd measure_clock arm (to see it adjust every 2 seconds)

To Display licensing/technical data about a program:
modinfo <program_name>

To adjust CPU clock and other settings in Raspberry Pi, navigate to:
cd /
boot/config.txt
and adjust via sudo nano
force_turbo=1
over_voltage=6-8(8max)
arm_freq=2000-2200(2200max)

To Update/Upgrade All Packages:
sudo pacman -Syu
OR

To install a specific package:
sudo pacman -S <name>
OR

To test whether or not a server is running on a specific port:

telnet localhost 3000

To uncompress a zip file:

unzip file.zip

To extract and uncompress a tar.gz file:

tar -xvzf foo.tar.gz

To change file permissions:

chmod (a somewhat advanced command, see chmod_notes.txt)

To remove a specific package:
sudo pacman -R <name>
OR

To remove a specific package and all its dependencies:
sudo pacman -Rsu <name>

To view/remove orphan packages:
pacman -Qdttq
sudo pacman -Rns $(pacman -Qdttq)


To clean up the pacman cache of all packages that are not currently installed (except for the last 3 packages):
sudo paccache -rvk3
More dangerous, removes entire cache:
sudo pacman -Scc

To clean out your /home directory cache:
First to see your home cache disk usage:
sudo du -sh ~/.cache/
And then to remove everything there:
sudo rm -rf ~/.cache/* (be careful with this command as rm -rf with a wildcard will delete EVERYTHING)

To remove orphan (unused packages):
First to see orphans run:
sudo pacman -Qtdq
And then to remove them
sudo pacman -Rns $(pacman -Qtdq)

To list any failed services:
sudo systemctl --failed

To check for any process errors run:
sudo journalctl -p 3 -xb

To install snap and enable classic:

sudo pacman -S snapd
sudo ln -s /var/lib/snapd/snap /snap

Install Codium using snap:
sudo snap install codium --classic (has issues with displaying user prompts, but other package managers have other issues...)

For Art Install the following:
gimp(should be default in most distros)
inkscape
krita
blender

To add Fonts:
Download Fonts and unzip them
move them to usr/share/fonts/<folder_name>

For Epson V30 scanner enter the following (for arch and manjaro):
pamac build iscan-plugin-gt-f720
pamac install iscan

To Install td ameritrade
Follow specific instructions from both website and AUR (make sure java 8 is installed)

Some packages (like Visual Studio Code) you'll want a very specific version of it that simply using pacman -S won't do.
For this, the Arch Developers have created a command called makepkg that runs a series of make or cmake related commands to
quickly and easily compile binary files.

Most of these PKGBUILD files can be downloaded using git clone from the official aur repositories (always research the binary before doing this).

git clone https:/aur.archlinux.org/etc.git

Then cd into the created directory, ls to see if there is a PKGBUILD (always take a look around using ls).

If you're ready to compile the program, simply type in
 makepkg -si

This will compile the program and if there are unresolved dependencies, it will download them and compile them as well.

If you get a fakeroot binary error, it usually means you haven't installed the dependency base-devel, simply

sudo pacman -S base-devel

Upgrade:
sudo pacman -Syu

Install specific kernel:
sudo pacman -S kernel501 (501 being changeable in this case to the kernel version number you want)

Install package:
sudo pacman -S <packagename>

See package dependencies:
pactree <packagename>

See package dependencies only 1 level deep:
pactree -d 1 <packagename>

See package dependencies only one level deep without tree format:
pactree -d -1 -u <packagename>

Remove package:
sudo pacman -R <packagename>

Remove package and all its dependencies:
sudo pacman -Rcns <packagename>

See which program owns this file:
sudo pacman -Qo /path/to/file

Other commands of note:

Create your own environment variables in bash:
export VAR=value (you can set custom paths to be navigated in bashrc, alias cvar="cd '$VAR'")

See the day you installed Linux (ie Birthday)
stat / | awk 'Birth: /{print $2}'

OpenBSD's doas:
sudo is a rather large program and is designed mainly for large scale systems administration purposes.
Because of this, it is not necessary for most home use cases.  Instead, you may wish to install opendoas as an alternative:

sudo pacman -S opendoas

You'll need to configure opendoas by creating a doas.conf file in your /etc directory:

sudo touch /etc/doas.conf

And input this single line command to permit doas access to the wheel (sudoers) group:
permit persist :wheel

You'll also need to change owership of this file to root and reset the file permissions:
sudo chown -c root:root /etc/doas.conf
sudo chmod -c 0400 /etc/doas.conf

This will allow it to act mainly as a lighter weight version of sudo

A note on doas: You probably do NOT want to remove sudo as certain programs
like makepkg rely on it (although this is a questionable practice).

To have btop start on startup and align to the left of the screen, go to Session and Startup and create a new operation:
xfce4-terminal --geometry=127x51+0+0 -x btop
Same with xbanish:
xbanish

Extracting gpg keys so that you can copy them without mouse:

In terminal, in directory with .gpg file
gpg -d secret_file.txt.gpg > echo > file_secrets.txt
Enter password for gpg when prompted

Use Micro to Copy text:
micro gh_token.txt
Ctrl + a
Ctrl + c
Ctrl + q

In main terminal:
Ctrl + shift + v

Config Files:
Configuration files for certain programs usually fall under the ~/.config directory, I have specifically created certain keybindings for example
which can be found in the file titled:

xfce4-keyboard-shortcuts.xml

You can copy these into a new installation of xfce by putting this file into the following directory:

~/.config/xfce4/xfconf/xfce-perchannel-xml

Allow infinite tries to log in (default is 3 attempts):
 Navigate to /etc/security/faillock.conf
 Change deny = 0

Other Apps of Mention:
alacritty (nice simple terminal emulator)

btop (best top, written in C++)
nvtop (nvidia graphical user interface to monitor GPU status)
vscode(after experimenting with other vscode versions, the official one with telemetry turned off is by far the best, git clone from aur, makepkg -si, make sure basedevel is installed)
micro(minimalist text editor)
irssi
tor-browser
nmap
mangohud (displays gpu, cpu temps and usage percentage in game, input into steam Launch Options the following:)
MANGOHUD_CONFIG="cpu_temp,gpu_temp,background_alpha=0.2, font_size=16, round_corners=5.0, gl_vsync=0" mangohud %command% --launcher-skip"
ecryptfs-simple (simple encrypter package that can encrypt directories/files)
encfs (like ecryptfs, but better, sudo pacman -S encfs)
mtr (like ping, but way better)
etcher
iscan (funny enough, it's in the local repos, but you can also get it from the AUR)
krita
inkscape
photogimp(plugin for gimp that gives it a more photoshop feeling ui download zip file from github, see brodie robertson's YT on installation)
greenwithenvy(gwe - nvidia overclock/fanspeed adjustment gui application)

xbanish (hides mouse on keyboard input, make sure to add to startup applications)
xbanish is definitely best called on start up, to do so, simply create a startup command from the whisker menu's startup GUI, and enter: xbanish

Laptop Battery Saving Utilities:
autocpufreq (one of the better battery saving measures, works more or less out of the box)
powertop (monitors mainly)
tlp (tlp start)
investigate cpu frequencies

Installing ecryptfs-simple:
git clone https://aur.archlinux.org/ecryptfs-simple.git
cd ecryptfs-simple
makepkg-si
(if your receive: "One or more PGP signatures could not be verified!, enter:)
gpg --recv-key <PGP public key listed above error>
makepkg-si

Favorite DE/TWM thus far:
Manjaro XFCE (minimal DE) (favorite thus far 2021)
Manjaro Sway (community driven TWM)
Manjaro I3 (community driven TWM)
Manjaro Lomiri (for Pinephone, still in beta version as of mid 2021)

Where you can find certain configuration files:
Neovim Configuration(~/.config/nvim/)
Bash Configuration (~/.bashrc)
Alacritty Configuration (~/.config/alacritty)
Custom XFCE Keyboard Configuration (~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-keyboard-shortcuts.xml)
Custom XFCE AutoStart Scripts <copy entire directory>(~/.config/autostart)
FireFox Settings (~/.mozilla/firefox/k6634gl6.dev-edition-default/prefs.js)