Basic Unix Commands

1. hostname
2. lsb_release -a
3. echo ~
4. who
5. history | grep /usr/bin | tail -n 5
6. wc -w /usr/dict/words
7. groups [id -G -n for extra marks]
8. find ~ -name \* -type f -print
9. man -k bash

Make sure you give proper citations for your work ;)

1: hostname
2: uname -a
3:
4: users
5: cat ~/.bash_history (last commands in current user) to do exactly what you ask for you have to use grep over /etv/passwd to get the list of users and the use it to cat everyones .bash_history file
6: 
7: cat /etc/passwd ans some grep wizardy
8:
9:

Others have answered your specific query. If you're interested in learning the shell you can do worse than read LinuxCommand.org. If you find yourself wishing to go further the Advanced Bash Scripting Guide is a great resource.