1. ls (switches)
2. pwd
3. cd (../.)
4. ifconfig
5. ping
6. clear 
7. debian distro repo (apt, apt-get)
9. history
11. touch
12. rm
13. mkdir
14. rmdir
13. manual (man/-h/--help)
14. cp
15. mv
17. cat
20. curl
21. echo
22. grep
23. hostname*
25. netstat
26. sort
30. Redirection and pipes

Useful files

1. /etc/passwd
2. /etc/shadow
3. /etc/os-release

User administration

8. uname (switches)*
18. adduser
19. passwd
27. sudo
28. who
29. whoami 
24. id
25. userdel


file permissions
16. chmod (numbers/+x)
18. chown
19. chgrp
10. prompt type