Fundamental of Shell script/command

Where am I in the computer?
```
pwd
```
How to create new directory ?
```
mkdir directory_name
```
How to go to a directary call 'test'?
```
cd test
```
How to create a text file?
```
touch test.txt
```
How to run a python file
```
python hello.py
```
How to install C++, Python, Fortran in Linux?
```
sudo apt-get install build essential
```
How to update Linux?
```
sudo apt-get update
```
How to know who are you?
```
whoaami
```
How to create tree of all files?
```
pstree
```
How to list all running process?
```
top
```