Based on my ubuntu:

  1. Shutdown
    • shutdown now
    • shutdown -r now
    • sudo shutdown -h now
  2. Ubuntu OS info and hardwares:
    • lsb_release -a
    • cat /proc/version
    • cat /etc/redhat-release
    • cat /proc/meminfo
    • cat /proc/cpuinfo | grep cores | uniq
    • lspci | grep VGA
    • lspci | grep 3D
  3. Disk:
    • df -h
    • du -h --max-depth=1
    • du -sh *
  4. Folder and File shortcut:
    • ln -s ~/Work/BackupProject ~/Desktop
    • ln filea filea_shortcut
  5. Group & Users:
    • cat /etc/group
    • cat /etc/passwd
  6. JAVA_HOME:
    • /usr/lib/jvm/java-8-openjdk-amd64/
  7. no hung up
    • nohup java -jar app.jar &
    • pidof java
  8. convert file encoding
    • dd conv=ascii if=start.sh of=start.sh.txt
  9. Redis
    • sudo service redis-server stop
    • ps aux | grep redis
    • redis-server &
    • redis-cli -h hostname -p port -a passphase
  10. find some file
    • find / -name app.jar
  11. de-package
    • sudo dpkg -i file.deb
  12. my local nginx config:
    • cd /etc/nginx/sites-enabled - ll
    • haohanwubian -> /etc/nginx/sites-available/haohanwubian
  13. firewall settings
    • sudo ufw enable
    • sudo ufw allow 8080/tcp comment 'my website'
    • sudo ufw allow 9000:9999/tcp
  14. create file with specific length
    • truncate -s 25M test.txt
    • fallocate -l 32000 test.txt
  15. random string 20 bytes
    • cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 20 | head -n 1
  16. random int between 0 and 65535
    • od -An -N2 -i /dev/urandom | tr -d ' '
  17. tar
    • tar -cvf test.tar test/
    • tar -xvf test.tar
    • tar -czvf test.tar.gz test/
    • tar -xzvf test.tar.gz
  18. md5sum
    • md5sum test.tar
    • sha256sum test.tar
    • sha512sum test.tar
  19. windows OS sha256
    • certutil -hashfile test.zip SHA256
  20. npm
    • npm config get registry
    • npm config set registry https://registry.npmmirror.com
  21. Uninstall a package
    • dpkg --list
    • sudo apt-get remove <package name> && sudo apt-get autoremove
  22. generate rsa keys and add rsa key to system
    • ssh-keygen
    • eval $(ssh-agent -s)
    • ssh-add /home/peter/.ssh/rsa_private
  23. git config
    • git config --global user.email "your_email@example.com"
    • git config --global user.name "your_name"
  24. SFTP :)
    • scp /path/to/local/file username@remote_server_address:/path/to/remote/directory
    • scp ~/files/1.jar username@10.10.10.10:/opt/apps
  25. MacOS telnet
    • nc -vz 192.168.11.110 3306
  26. MacOS remove extra attr
    • xattr -d com.apple.quarantine /opt/chromedriver-mac-arm64/chromedriver
  27. MacOS check which process takes port 8000
    • lsof -i :8000