CIS120 Book

CIS120 Linux Fundamentals by Scott Shaper

mkdir Command

Think of the mkdir command as your digital folder creator. Just like you create folders on your desktop to organize files, mkdir helps you create directories (folders) in Linux to keep your files organized.

The examples below use the course setup. Work in ~/playground/chapter2 so you can create directories there alongside the existing practice files.

Why Use mkdir?

You'll use mkdir when you want to:

Create a new folder for your project
Organize your files into categories
Set up a directory structure for a new task
Create multiple folders at once

Basic Usage

The simplest way to create a directory is:

mkdir directory_name

For example, to create a folder in your chapter 2 playground:

cd ~/playground/chapter2
mkdir class_notes

Common Options

Option	What It Does	When to Use It
`-p`	Creates parent directories if they don't exist	When creating nested folders
`-v`	Shows what's being created	When you want to see the process
`-m`	Sets permissions for the new directory	When you need specific access rights
`-Z`	Sets SELinux security context	When working with SELinux systems
`--context`	Like -Z but specifies full context	When you need specific SELinux settings
`--mode`	Same as -m but more explicit	When you want to be very clear about permissions
`--parents`	Same as -p but more explicit	When you want to be very clear about parent creation
`--verbose`	Same as -v but more explicit	When you want to be very clear about verbosity
`--help`	Shows help information	When you need to see all options
`--version`	Shows version information	When you need to check the version

Practical Examples

Creating a Single Directory

From ~/playground/chapter2, create a folder for a project:

cd ~/playground/chapter2
mkdir my_project

Creating Multiple Directories

You can create several folders at once in the chapter 2 playground:

cd ~/playground/chapter2
mkdir notes homework projects

Creating Nested Directories

To create a folder inside another folder (even if the parent doesn't exist), use -p. From ~/playground/chapter2:

cd ~/playground/chapter2
mkdir -p school/spring2024/cs101/assignments

This creates school, then school/spring2024, then school/spring2024/cs101, then school/spring2024/cs101/assignments in one command.

Creating with Permissions

To create a directory with specific access rights (for example in your chapter 2 playground):

cd ~/playground/chapter2
mkdir -m 755 shared_folder

This creates a folder that you can read, write, and execute, while others can only read and execute.

Tips for Success

Use descriptive names: Make your directory names clear and meaningful
Use -p for nested directories: It saves time and prevents errors
Check your current location: Use pwd to confirm you're in ~/playground/chapter2 (or where you want the new folders)
Use -v when learning: It helps you understand what's happening

Common Mistakes to Avoid

Creating directories with spaces in names (use underscores instead)
Forgetting the -p option when creating nested directories
Not checking if a directory already exists
Using special characters in directory names

Best Practices

Keep directory names short but descriptive
Use lowercase letters for consistency
Use underscores instead of spaces
Create a logical folder structure