# check for updates
sudo apt-get update
​
# upgrade
sudo apt-get upgrade
​
# install new package
sudo apt-get install new_package
​
# cleanup
sudo apt-get autoremove
​
# Fix missing keys
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 4B8EC3BAABDC4346

# find process running on port 5000
sudo lsof -i tcp:5000
​
# kill a process with pid 1990
kill -9 1990
​
# find and kill a process running on port 5000
sudo kill $( sudo lsof -i tcp:5000 -t )
​
# kill all processes named Google Chrome Helper
killall -9 "Google Chrome Helper"

# check docker usage
sudo docker stats
​
# check process usage
top
​
# check memory usage
free -h
​
# check disk usage
df -lh
​
# list all directories in current folder with their size
du -h

# full process tree
ps -axfo pid,uname,cmd

# check application certificate
spctl -a -vv /Applications/Google\ Chrome.app
# /Applications/Google Chrome.app: accepted
# source=Notarized Developer ID
# origin=Developer ID Application: Google, Inc. (EQHXZ8M8AV)

# gzip compression on a tar archiv: tar_file files_or_folder_to_be_compressed
tar cvzf my-files.tar.gz ./my-files
​
# unzip a tar file
tar xvzf my-files.tar.gz

# Find a file by name on your machine
sudo find / -name 'secret.txt'
​
# delete backup files
sudo find . -name "*.bak" -delete

apt-get update && apt-get install -yq gconf-service libasound2 libatk1.0-0 libatk-bridge2.0-0 libc6 libcairo2 libcups2 libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 libxtst6 ca-certificates fonts-liberation libappindicator1 libnss3 lsb-release xdg-utils wget x11vnc x11-xkb-utils xfonts-100dpi xfonts-75dpi xfonts-scalable xfonts-cyrillic x11-apps xvfb
apt-get update && apt-get install -y wget --no-install-recommends \
    && wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add - \
    && sh -c 'echo "deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list' \
    && apt-get update \
    && apt-get install -y google-chrome-unstable fonts-ipafont-gothic fonts-wqy-zenhei fonts-thai-tlwg fonts-kacst ttf-freefont \
    --no-install-recommends \
    && rm -rf /var/lib/apt/lists/* \
    && apt-get purge --auto-remove -y curl \
    && rm -rf /src/*.deb

COUNTER=0
while [  $COUNTER -lt 10 ]; do
    echo The counter is $COUNTER
    let COUNTER=COUNTER+1
done

COUNTER=20
until [  $COUNTER -lt 10 ]; do
    echo COUNTER $COUNTER
    let COUNTER-=1
done