BONUS: learn directory structure

This is an exercise in how your computer is organized into directories (folders) and files

preview

I will build the structure below step by step to see how files and folders are related like a family tree, and at the end will know how to move around in the structure because I will understand the relationships.

parent
├── a_file_in_parent
├── aka_grandparent_of_child_of_child
├── aka_grandparent_of_child_of_sibling_of_child
├── child
│   ├── a_file_in_child
│   ├── aunt_or_uncle_of_another_grandchild_of_parent
│   └── child_of_child
│       ├── a_file_in_child_of_child
│       ├── a_grandchild_of_parent
│       └── cousin_of_child_of_sibling_of_child
└── sibling_of_child
    ├── a_file_in_sibling_of_child
    ├── aunt_or_uncle_of_a_grandchild_of_parent
    └── child_of_sibling_of_child
        ├── a_file_in_child_of_sibling_of_child
        ├── another_grandchild_of_parent
        └── cousin_of_child_of_child

You will become familiar with these commands

questions about directory structure

Here are questions you can answer after going through this chapter

What is a folder (directory)?
what is a file?
How can I tell what directory I am in?
How can I change directories?
How can I make a directory?
How can I see directory relationships?
How can I list what is in a directory?
How can I make an empty file?
How can I use directory relationships?
How can I remove a directory and everything inside it?

what is a folder?

A folder (directory) is a container for files. It helps organize things, just like a folder in a file cabinet is used to put files that belong together in one place.

I keep every project I work on in its own folder (directory). All the code from this book is kept in a folder named pumping_python

what is a file?

A file is a collection or container for text, like paper we write or print on and keep in a folder. Their names usually end with an extension (optionally) to show the type of file. For example

.txt for a plain text file
.sh for a bash file
.ps1 for a PowerShell file
.py for a Python module

requirements

I open a terminal to make sure the tree program is installed by typing this

tree

when it is not installed on the computer, the terminal shows

tree: command not found

when it is installed, the terminal shows a tree of directories and files. The tree program shows how files and folders on a computer are related.

how to install tree

how to install tree on Linux/Windows Subsystem for Linux
how to install tree on Mac OS
how to install tree on Windows without Windows Subsystem for Linux

how to install tree on Linux/Windows Subsystem for Linux

sudo apt update

optionally, you can do a full upgrade if you want

sudo apt full-upgrade --yes

type this in the terminal to install tree

sudo apt install tree

continue in how to work in directories

how to install tree on Windows without Windows Subsystem for Linux

tree comes with Windows you do not have to do anything. The following are things you would type in place of what I have in the chapter

New-Item instead of touch
tree /F instead of tree
dir instead of ls --all/-a

The path shown when you call pwd or tree shows \ instead of /, for example

...\pumping_python

instead of

.../pumping_python

continue with how to work in directories

how to install tree on Mac OS

install brew (The Missing Package Manager for MacOS), if you do not have it already
```
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
```
the terminal shows instructions about how to add brew to your path
copy and paste the 3 lines it shows in the terminal then hit return to run it, the terminal will not show anything if the commands run successfully
use brew to install tree
```
brew install tree
```
continue with how to work in directories

how to work in directories

how to see the directory I am in

I start by checking where I am in the terminal. I can do this with the pwd program

pwd

the terminal shows

.../pumping_python

because I am in the pumping_python folder

pwd shows the path/address to the current folder I am in at the moment

Note

If you see the same name, skip to the part where I create parent. If you see a different name, continue to the next step how to change directory.

how to change directory

I use the cd program to change directories

cd pumping_python

the terminal shows

cd: pumping_python: No such file or directory

this means the folder does not exist where I am

how to make a directory

I use the mkdir program to make a folder (directory)
```
mkdir pumping_python
```
the terminal goes back to the command line
I use cd to change directory again
```
cd pumping_python
```
the terminal shows I am now in the pumping_python folder (directory)
```
.../pumping_python
```
Tip

to make sure I can see the pumping_python folder in my Integrated Development Environment (IDE) I have to open the folder. Here’s how to do that with Visual Studio Code
```
code .
```
a new Visual Studio Code window opens in the pumping_python directory

I want to work in a directory named parent

cd parent

the terminal shows

cd: no such file or directory: parent

I make the directory
```
mkdir parent
```
the terminal shows
```
.../pumping_python
```
I change directory to the folder to do some work in it
```
cd parent
```
the terminal shows
```
.../pumping_python/parent
```
I am in the parent folder I just made
I use pwd to see where I am
```
pwd
```
the terminal shows
```
.../pumping_python/parent
```

how to list what is in a directory

I can use ls to show what is in a directory and see information about the files in it
```
ls
```
the terminal goes back to the command line
```
.../pumping_python/parent
```
this directory is empty. ls has a few options, I try it again with one of them
```
ls --all
```
Attention

on MacOS you may get this error
```
ls: unrecognized option '--all'
```
--all is the long form of the option, and there is usually a short form, use it instead
```
ls -a
```
on Windows without Windows Subsystem for Linux use dir /ah instead of ls -a
```
dir /ah
```
the terminal does not show . and ..
the terminal shows
```
.  ..
```
- --all/-a tells ls to show things in the directory that start with ., these are hidden by default
- . represents the current directory
I try to change directory to the .
```
cd .
```
the terminal shows
```
.../pumping_python/parent
```
- I am still in the same folder
- . is used for the directory I am in, which is parent in this case
I try cd with .. to see what happens
```
cd ..
```
the terminal shows
```
.../pumping_python
```
- .. is used for the parent of a directory where I am
- pumping_python is the parent of parent
I go back to parent
```
cd parent
```
the terminal shows
```
.../pumping_python/parent
```

how to look at directory structure

I can use the tree program to see what files and folders are in a directory. I type it in the terminal to see what is in the parent directory
```
tree
```
on Windows without Windows Subsystem for Linux use tree /F instead of tree
```
tree /F
```
the terminal shows
```
.

0 directories, 0 files
```
it is empty
I change directory
```
cd child
```
the terminal shows
```
cd: no such file or directory: child
```
the directory does not exist
I make the folder
```
mkdir child
```
the terminal goes back to the command line
I use ls to see what is now in parent
```
ls -a
```
on Windows without Windows Subsystem for Linux use dir /ah instead of ls -a
```
dir /ah
```
the terminal shows
```
.  ..  child
```

I use tree to see the structure

tree

the terminal shows

.
└── child

2 directories, 0 files

I try to go to a different directory

cd sibling_of_child

the terminal shows

cd: no such file or directory: sibling_of_child

the directory does not exist

I make a new folder
```
mkdir sibling_of_child
```
the terminal goes back to the command line
I use ls to see what is in parent now
```
ls -a
```
the terminal shows
```
.  ..  child  sibling_of_child
```

I use tree to see the structure

tree

the terminal shows

.
├── child
└── sibling_of_child

3 directories, 0 files

I change directory to one of the children of parent
```
cd child
```
the terminal shows
```
…/pumping_python/parent/child
```
I list the contents of the folder
```
ls
```
the terminal goes back to the command line. I use ls with the short form of the --all option
```
ls -a
```
the terminal shows
```
.  ..
```
I use tree
```
tree
```
the terminal shows
```
.

0 directories, 0 files
```

I change directory

cd child_of_child

the terminal shows

cd: child_of_child: No such file or directory

I make the directory

mkdir child_of_child

the terminal goes back to the command line

I try to go to child_of_child again

cd child_of_child

the terminal shows

.../parent/child/child_of_child

I go up a level to the parent of child_of_child
```
cd ..
```
the terminal shows
```
.../parent/child
```
I am back in child
I go up another level to the parent of child
```
cd ..
```
the terminal shows
```
.../pumping_python/parent
```
I am back in parent

I change directory to the other child of parent

cd sibling_of_child

the terminal shows

…/pumping_python/parent/sibling_of_child

I list the contents of the folder
```
ls
```
the terminal goes back to the command line. I use ls with the short form of the --all option
```
ls -a
```
the terminal shows
```
.  ..
```
I use tree
```
tree
```
the terminal shows
```
.

0 directories, 0 files
```

I change directory to a child of this folder

cd child_of_sibling_of_child

the terminal shows

cd: child_of_sibling_of_child: No such file or directory

I make the directory

mkdir child_of_sibling_of_child

the terminal goes back to the command line

I try to go to child_of_sibling_of_child again

cd child_of_sibling_of_child

the terminal shows

.../parent/sibling_of_child/child_of_sibling_of_child

I go up a level to the parent of child_of_sibling_of_child
```
cd ..
```
the terminal shows
```
.../parent/sibling_of_child
```
I am back in sibling_of_child
I go up another level to the parent of sibling_of_child
```
cd ..
```
the terminal shows
```
.../pumping_python/parent
```
I am back in parent

I show the directory structure

tree

on Windows without Windows Subsystem for Linux use tree /F instead of tree

tree /F

the terminal shows

.
├── child
│   └── child_of_child
└── sibling_of_child
    └── child_of_sibling_of_child

5 directories, 0 files

how to make an empty file

I can make empty files in a folder with the touch program

I add an empty file to parent
```
touch a_file_in_parent
```
on Windows without Windows Subsystem for Linux use New-Item instead of touch
```
New-Item a_file_in_parent
```
the terminal goes back to the command line
I use ls to see what is in the folder now
```
ls -a
```
on Windows without Windows Subsystem for Linux use dir /ah instead of ls -a
```
dir /ah
```
the terminal does not show . and ..
the terminal shows
```
.  ..  a_file_in_parent  child  sibling_of_child
```
I change directory to one of the children of parent
```
cd child
```
the terminal shows
```
.../pumping_python/parent/child
```
I add an empty file with touch
```
touch a_file_in_child
```
the terminal goes back to the command line

I list the contents of the folder

ls -a

the terminal shows

.  ..  a_file_in_child  child_of_child

I change directory to the parent of child
```
cd ..
```
the terminal shows
```
.../pumping_python/parent
```

I change directory to the other child of parent

cd sibling_of_child

the terminal shows

.../pumping_python/parent/sibling_of_child

I add an empty file with touch
```
touch a_file_in_sibling_of_child
```
the terminal goes back to the command line

I list the contents of the folder

ls -a

the terminal shows

.  ..  a_file_in_sibling_of_child  child_of_sibling_of_child

I change directory to the parent of sibling_of_child
```
cd ..
```
the terminal shows
```
.../pumping_python/parent
```

I use tree

tree

the terminal shows

.
├── a_file_in_parent
├── child
│   ├── a_file_in_child
│   └── child_of_child
└── sibling_of_child
    ├── a_file_in_sibling_of_child
    └── child_of_sibling_of_child

5 directories, 3 files

Tip

Your terminal may use colors to show the difference between directories and files

I want to make a file in child_of_child. I use change directory to go to its parent first
```
cd child
```
the terminal shows
```
/pumping_python/parent/child
```
I change directory to child_of_child
```
cd child_of_child
```
the terminal shows
```
.../parent/child/child_of_child
```

how to use directory relationships

I can go from child_of_child to parent in 1 step by using ..
```
cd ../..
```
the terminal shows
```
.../pumping_python/parent
```
Since .. is for the parent of a directory, ../.. is for the parent of a parent, that is a grandparent. I can use as many ..’s I need for each parent, for example ../../../.. would be the great great grand parent
I try to go from parent to child_of_child in 1 step
```
cd child_of_child
```
the terminal shows
```
cd: child_of_child: No such file or directory
```
I cannot get to child_of_child without its parent
I try to go from parent to child_of_child in 1 step with its parent
```
cd child/child_of_child
```
the terminal shows
```
.../parent/child/child_of_child
```
I make an empty file
```
touch a_grandchild_of_parent
```
the terminal goes back to the command line
I use ls to list the contents of the folder
```
ls -a
```
the terminal shows
```
.  ..  a_grandchild_of_parent
```
I go back to parent
```
cd ../..
```
the terminal shows
```
.../pumping_python/parent
```
I want to make a file in child_of_sibling_of_child. I use change directory to go to its parent first
```
cd sibling_of_child
```
the terminal shows
```
/pumping_python/parent/sibling_of_child
```
I change directory to child_of_sibling_of_child
```
cd child_of_sibling_of_child
```
the terminal shows
```
.../parent/sibling_of_child/child_of_sibling_of_child
```
I go from child_of_sibling_of_child to parent in 1 step
```
cd ../..
```
the terminal shows
```
.../pumping_python/parent
```
I try to go from parent to child_of_sibling_of_child in 1 step
```
cd child_of_sibling_of_child
```
the terminal shows
```
cd: child_of_sibling_of_child: No such file or directory
```
I can only go directly to folders that exist where I am or use the path to the folder I want to go to

I go from parent to child_of_sibling_of_child in 1 step with its parent

cd sibling_of_child/child_of_sibling_of_child

the terminal shows

.../parent/sibling_of_child/child_of_sibling_of_child

I make an empty file
```
touch another_grandchild_of_parent
```
the terminal goes back to the command line
I use ls to list the contents of the folder
```
ls -a
```
the terminal shows
```
.  ..  another_grandchild_of_parent
```
I go back to parent
```
cd ../..
```
the terminal shows
```
.../pumping_python/parent
```
I add an empty file
```
touch aka_grandparent_of_child_of_child
```
the terminal goes back to the command line
I make another empty file
```
touch aka_grandparent_of_child_of_sibling_of_child
```
the terminal goes back to the command line

I use tree to see what parent looks like now

tree

on Windows without Windows Subsystem for Linux use tree /F instead of tree

tree /F

the terminal shows

.
├── a_file_in_parent
├── aka_grandparent_of_child_of_child
├── aka_grandparent_of_child_of_sibling_of_child
├── child
│   ├── a_file_in_child
│   └── child_of_child
│       └── a_grandchild_of_parent
└── sibling_of_child
    ├── a_file_in_sibling_of_child
    └── child_of_sibling_of_child
        └── another_grandchild_of_parent

5 directories, 7 files

I can add an empty file in 1 step in any directory as long as
- I know its path
- I know its relation to where I am and
- I have permission to write to the folder
I add another empty file in child
```
touch child/aunt_or_uncle_of_another_grandchild_of_parent
```
on Windows without Windows Subsystem for Linux use New-Item instead of touch
```
New-Item child/aunt_or_uncle_of_another_grandchild_of_parent
```
the terminal goes back to the command line
I add another empty file in sibling_of_child
```
touch sibling_of_child/aunt_or_uncle_of_a_grandchild_of_parent
```
the terminal goes back to the command line

I use tree

tree

the terminal shows

.
├── a_file_in_parent
├── aka_grandparent_of_child_of_child
├── aka_grandparent_of_child_of_sibling_of_child
├── child
│   ├── a_file_in_child
│   ├── aunt_or_uncle_of_another_grandchild_of_parent
│   └── child_of_child
│       └── a_grandchild_of_parent
└── sibling_of_child
    ├── a_file_in_sibling_of_child
    ├── aunt_or_uncle_of_a_grandchild_of_parent
    └── child_of_sibling_of_child
        └── another_grandchild_of_parent

5 directories, 9 files

I add an empty file in child_of_child
```
touch child/child_of_child/a_file_in_child_of_child
```
the terminal goes back to the command line

I add an empty file in child_of_sibling_of_child

touch sibling_of_child/child_of_sibling_of_child/a_file_in_child_of_sibling_of_child

on Windows without Windows Subsystem for Linux use New-Item instead of touch

New-Item sibling_of_child/child_of_sibling_of_child/a_file_in_child_of_sibling_of_child

the terminal goes back to the command line

I change directory to the parent of parent
```
cd ..
```
the terminal shows
```
.../pumping_python
```

I use tree to show what is in parent

tree parent

the terminal shows

parent
├── a_file_in_parent
├── aka_grandparent_of_child_of_child
├── aka_grandparent_of_child_of_sibling_of_child
├── child
│   ├── a_file_in_child
│   ├── aunt_or_uncle_of_another_grandchild_of_parent
│   └── child_of_child
│       ├── a_file_in_child_of_child
│       └── a_grandchild_of_parent
└── sibling_of_child
    ├── a_file_in_sibling_of_child
    ├── aunt_or_uncle_of_a_grandchild_of_parent
    └── child_of_sibling_of_child
        ├── a_file_in_child_of_sibling_of_child
        └── another_grandchild_of_parent

5 directories, 11 files

I type pwd to show where I am
```
pwd
```
the terminal shows
```
.../pumping_python
```

I can list the contents of any folder once I know its path or relation to where I am

ls -a parent

the terminal shows

.                 aka_grandparent_of_child_of_child             sibling_of_child
..                aka_grandparent_of_child_of_sibling_of_child
a_file_in_parent  child

I list the contents of child

ls -a parent/child

the terminal shows

.   a_file_in_child                                child_of_child
..  aunt_or_uncle_of_another_grandchild_of_parent

I list the contents of child_of_child

ls -a parent/child/child_of_child

the terminal shows

.  ..  a_file_in_child_of_child  a_grandchild_of_parent

I list the contents of sibling_of_child

ls -a parent/sibling_of_child

the terminal shows

.   a_file_in_sibling_of_child               child_of_sibling_of_child
..  aunt_or_uncle_of_a_grandchild_of_parent

I list the contents of child_of_sibling_of_child

ls -a parent/sibling_of_child/child_of_sibling_of_child

the terminal shows

.  ..  a_file_in_child_of_sibling_of_child  another_grandchild_of_parent

I change directory to child_of_child
```
cd parent/child/child_of_child
```
I want to list the contents of child_of_sibling_of_child from inside child_of_child in 1 step. ../.. is parent and I can go from parent to child_of_sibling_of_child, I use the relationship with ls
```
ls -a ../../sibling_of_child/child_of_sibling_of_child
```
the terminal shows
```
.  ..  a_file_in_child_of_sibling_of_child  another_grandchild_of_parent
```
I add an empty file to child_of_sibling_of_child from child_of_child
```
touch ../../sibling_of_child/child_of_sibling_of_child/cousin_of_child_of_child
```
the terminal goes back to the command line

I use tree this time

tree ../../sibling_of_child/child_of_sibling_of_child

the terminal shows

../../sibling_of_child/child_of_sibling_of_child
├── a_file_in_child_of_sibling_of_child
├── another_grandchild_of_parent
└── cousin_of_child_of_child

1 directory, 3 files

I can use the same thing to change directory to child_of_sibling_of_child from child_of_child

cd ../../sibling_of_child/child_of_sibling_of_child

the terminal shows

.../parent/sibling_of_child/child_of_sibling_of_child $

I want to list the contents of child_of_child from inside child_of_sibling_of_child in 1 step. Since ../.. is parent and I can go from parent to child_of_child, I use the relationship with ls
```
ls -a ../../child/child_of_child
```
the terminal shows
```
.  ..  a_file_in_child_of_child  a_grandchild_of_parent
```
I add an empty file to child_of_child from child_of_sibling_of_child
```
touch ../../child/child_of_child/cousin_of_child_of_sibling_of_child
```
the terminal goes back to the command line

I use tree to show what is in child_of_child now

tree ../../child/child_of_child

the terminal shows

../../child/child_of_child
├── a_file_in_child_of_child
├── a_grandchild_of_parent
└── cousin_of_child_of_sibling_of_child

1 directory, 3 files

I look at the structure of parent again, this time from inside child_of_sibling_of_child

tree ../../../parent

the terminal shows

../../../parent
├── a_file_in_parent
├── aka_grandparent_of_child_of_child
├── aka_grandparent_of_child_of_sibling_of_child
├── child
│   ├── a_file_in_child
│   ├── aunt_or_uncle_of_another_grandchild_of_parent
│   └── child_of_child
│       ├── a_file_in_child_of_child
│       ├── a_grandchild_of_parent
│       └── cousin_of_child_of_sibling_of_child
└── sibling_of_child
    ├── a_file_in_sibling_of_child
    ├── aunt_or_uncle_of_a_grandchild_of_parent
    └── child_of_sibling_of_child
        ├── a_file_in_child_of_sibling_of_child
        ├── another_grandchild_of_parent
        └── cousin_of_child_of_child

5 directories, 13 files

I change directory to the parent of parent
```
cd ../../..
```
the terminal shows
```
.../pumping_python
```
I show the current working directory (where I am)
```
pwd
```
the terminal shows
```
.../
```

how to remove a directory and all its contents

I remove parent and all its descendants

Danger

This is a desctructive operation that CANNOT be undone on MacOS or Linux/Windows Subsystem for Linux, use it wisely
```
rm -rf parent
```
on Windows without Windows Subsystem for Linux use Remove-Item -Recurse -Force instead of rm -rf
```
Remove-Item -Path parent -Recurse -Force
```
the terminal goes back to the command line
- rm is used to remove files and folders
- -r/-Recurse means remove child directories and what is in them recursively, it goes through each child directory and removes everything include their children
- -f/-Force means “force”, do not ask me any questions, just remove the file or folder and all its children with extreme prejudice

I try to go back to the parent directory

cd parent

the terminal shows

cd: no such file or directory: parent

review

I ran the following commands to play with folder (directory) structure

How many questions can you answer after going through this chapter?

code from the chapter

Do you want to see all the CODE I typed in this chapter?

what is next?

Would you like to see me make a Test Driven Development Environment

BONUS: learn directory structure

preview

questions about directory structure

what is a folder?

what is a file?

requirements

how to install tree

how to install tree on Linux/Windows Subsystem for Linux

how to install tree on Windows without Windows Subsystem for Linux

how to install tree on Mac OS

how to work in directories

how to see the directory I am in

how to change directory

how to make a directory

how to list what is in a directory

how to look at directory structure

how to make an empty file

how to use directory relationships

how to remove a directory and all its contents

review

code from the chapter

what is next?

please leave a review