useradd username

useradd -m username

cat file | sed -e 's/\(o\)/-\1-/g'

sed -i -e 's/\(o\)/-\1-/g' file

cat file | awk '{ print $2 " " $1 " " $4 " " $3 " " $6 " " $5 }'

Content seperated by ';' cat file | awk -F ';' '{ print $2 " " $1 " " $4 " " $3 " " $6 " " $5}'

var1="$(hostname -f)" cat file | awk -v hostname="$var1" '{ print hostname " column1: " $1}'

cat file | awk 'BEGIN { print "Header" } { print $1} END { print "Footer" }'

tar zcvf file.tar.gz file

tar zxf file.tar.gz

tar xzf files.tar.gz file3

tar ztf file.tar.gz

fdisk -l

fdisk /dev/sda d n p p w

resize2fs /dev/sda

fdisk -l

pvcreate /dev/sdb

vgextend my_cool_vg /dev/sdb

lvextend -l +100%FREE /dev/my_cool_vg/root

resize2fs /dev/my_cool_vg/root

df

df -h

df -i

du -xh / | sort -rh | head -n 5

docker run -e 'MYSQL_ALLOW_EMPTY_PASSWORD=true' -d mysql:latest

docker exec -it 75470e66ae05 bash

cat << "EOF" > Dockerfile FROM debian:latest ENV MY_VARIABLE="Hello" WORKDIR /work COPY . /work RUN /bin/bash EOF docker build . -t my_image

kubectl run -it --rm docker.io/debian -- /bin/bash

podman run -it --rm docker.io/debian -- /bin/bash

:wq ZZ

:q! ZQ

:colorscheme darkblue :colorscheme # to see all color schemes

enable :set relativenumber toggle :set relativenumber!

enable :set number toggle :set number!

:!echo "Hi"

:r !echo "Command output"

list=('item1' 'item2' 'item3' 'item4') for item in $list[@]; do echo This is "$item" done

(return 0) && echo "Bla" Bla (return 1) && echo "Bla" # no output since the first condition failed

(return 0) || echo "Bla" # returns nothing since the first condition was true (return 1) || echo "Bla" Bla

NAME="DirtyDan" if [[ $NAME == "Marvin" ]]; then echo "Hi Marvin" elif [[ $NAME == "DirtyDan" ]]; then echo "I am the dirty Dan" else echo "Who tf are you" fi

# Empty string [[ -z STRING ]] # Not empty string [[ -n STRING ]] # Equal [[ STRING == STRING ]] # Not Equal [[ STRING != STRING ]] # Equal [[ NUM -eq NUM ]] # Not equal [[ NUM -ne NUM ]] # Less than [[ NUM -lt NUM ]] # Less than or equal [[ NUM -le NUM ]] # Greater than [[ NUM -gt NUM ]] # Greater than or equal [[ NUM -ge NUM ]] # Regexp [[ STRING =~ STRING ]] # Numeric conditions (( NUM < NUM )) # If OPTIONNAME is enabled [[ -o noclobber ]] # Not [[ ! EXPR ]] # And [[ X && Y ]] # Or [[ X || Y ]] # Exists [[ -e FILE ]] # Readable [[ -r FILE ]] # Symlink [[ -h FILE ]] # Directory [[ -d FILE ]] # Writable [[ -w FILE ]] # Size is > 0 bytes [[ -s FILE ]] # File [[ -f FILE ]] # Executable [[ -x FILE ]] # File 1 is more recent than 2 [[ FILE1 -nt FILE2 ]] # File 2 is more recent than 1 [[ FILE1 -ot FILE2 ]] # Same files [[ FILE1 -ef FILE2 ]]

# Integer declare -i # Array declare -a # Dictionary declare -A # Lower case letters declare -l # Uppercase letters declare -u # Print attributes and options of variable declare -p # Export variable declare -x # Function declare -f # Print name and attributes of function declare -F # Variable that references other variable declare -n

# Avoid overlay files (redirect via ">") set -o noclobber # Used to exit upon error, avoiding further execution set -o errexit # Unveils hidden failures set -o pipefail # Exposes unset variables set -o nounset

# Non-matching globs are removed ("*.txt" => "") shopt -s nullglob # Non-matching globs throw errors shopt -s failglob # Case insensitive globs shopt -s nocaseglob # Wildcards match dotfiles ("*.txt" => ".file.txt") shopt -s dotglob # Allow ** for recursive matches ("dir/**/*.txt" => "dir/subdir/subdir/file.txt") shopt -s globstar

echo "Hey I am content" > file

echo "Hey I am new content" >> file

cat << EOF > config_file # My config ip=10.1.1.1/32 EOF

cat << EOF >> config_file # Appended config port=9001 EOF

MY_VARIABLE="Content of my variable" cat << "EOF" >> config_file # Appended escaped config file="example" directory=$MY_VARIABLE EOF

use database altislife; show tables;

select sha("password");

create user "username"@"%" identified by "password";

create database database_name;

grant all privileges on database_name.* to "username"@"%"; flush privileges;

dictionary = { 'key1': 'value1', 'key2': 'value3', }

screen

screen -S screen_name

screen /usr/bin/some_script.sh

tmux

tmux new -s session_name

tmux ls

tmux attach -t session_name

Keyboard shortcut: CTRL + b + d

tmux kill-session -t session_name

# Clone repository git clone git@vmgitlab.fritz.box:gene/playground.git # Clone repository with specific folder name git clone git@vmgitlab.fritz.box:gene/playground.git my_repositroy

# Add single file git add README.md # Add all files (including sub directories) git add .

git commit -m 'message'

git pull

git push

git branch

git branch -c new_branch

git branch -d old_branch

# Change to branch git checkout branch # Change to commit git checkout 8350feb7ef876f6a644a8f99ff3ad3fda48f87a1 # change to tag git checkout v1.0.0

git init

# Create gitignore file in the root of the repository touch .gitignore Ignore file named .env echo '.env' >> .gitignore Ignore files with .txt suffix echo '*.txt' >> .gitignore Ignore files with .txt suffix including sub directories echo '**.txt' >> .gitignore

git clean

git reset