Basic Unix Commands

Question

I am new to Linux and I am trying to create a cheat-sheet to help me remember common bash commands. If you know any of the commands for the tasks below, please post them. I appreciate it!

Commands for:

1. the hostname of the system you are on?
2. the type and version of the operating system the machine machine is running?
3. the full path to your home directory?
4. which other users are logged into the machine you are using?
5. the last five commands executed by anyone from /usr/bin?
6. how many words there are in the spell check dictionary (/usr/dict/words)?
7. what groups you belong to?
8. what files (excluding directories) are located in your home directory and all its subdirectories?
9. what man pages have references to 'bash'?

Answer 1

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 ;)

Answer 2

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:

Answer 3

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.

Answer 4

what files (excluding directories) are located in your home directory and all its subdirectories?

$ cd $HOME
$ find -name \* -type f -print

btw. most of these commands are not bash builtins, rather standalone programs. So you can use them from any shell.

Answer 5

1. $ hostname

2. $ cat /etc/*release

   Note: this works on most distributions except plain Debian. On debian, 'cat /etc/debian_version'

3. $ echo ~

4. $ w

5. $ history |grep /usr/bin

   Will only show the history for that user. Not sure about a system-wide history. Maybe I can learn something here.

6. $ wc -l $(find /usr/share/dict -follow -type f -print) |grep total

   Assuming multiple word files and no duplicate words. Now follows symlinks!

7. $ groups

8. $ find ~ -type f

9. $ grep -R bash /usr/share/man

I also feel like I just did some kid's homework. And the formatting on this site is a nightmare.