mkdir (create directories) in Linux CLI - Step-by-Step Execution

Concept Flow - mkdir (create directories)

Start

↓

Run mkdir command

↓

Check if directory exists

↓

Create directory

↓

End

The mkdir command tries to create a directory. If the directory exists, it shows an error unless options are used.

Execution Sample

Linux CLI

mkdir myfolder
mkdir myfolder
mkdir -p myfolder/subfolder

Creates a directory 'myfolder', tries to create it again (error), then creates 'myfolder/subfolder' with -p option.

Execution Table

Step	Command	Directory Exists?	Action Taken	Output
1	mkdir myfolder	No	Create 'myfolder'
2	mkdir myfolder	Yes	Error: directory exists	mkdir: cannot create directory ‘myfolder’: File exists
3	mkdir -p myfolder/subfolder	Yes (myfolder), No (subfolder)	Create 'subfolder' inside 'myfolder'

💡 After step 3, all directories exist; command ends successfully.

Variable Tracker

Directory	Start	After Step 1	After Step 2	After Step 3
myfolder	Does not exist	Exists	Exists	Exists
myfolder/subfolder	Does not exist	Does not exist	Does not exist	Exists

Key Moments - 2 Insights

Why does the second mkdir command give an error?

Because 'myfolder' already exists after step 1, so trying to create it again without -p causes an error (see step 2 in execution_table).

What does the -p option do in mkdir?

It creates parent directories as needed and does not error if the directory exists, allowing nested directories creation (see step 3).

Visual Quiz - 3 Questions

Look at the execution table, what is the output of step 2?

A No output, directory created

B Directory created with no error

C mkdir: cannot create directory ‘myfolder’: File exists

D Permission denied error

💡 Hint

Check the 'Output' column for step 2 in the execution_table.

At which step does 'myfolder/subfolder' get created?

A Step 2

B Step 3

C Step 1

D It is never created

💡 Hint

Look at the 'Directory Exists?' and 'Action Taken' columns for 'myfolder/subfolder' in the execution_table.

If we remove the -p option from step 3, what would happen?

A Error because 'myfolder/subfolder' parent missing

B Subfolder is created anyway

C Error because 'myfolder' does not exist

D No error, command ignored

💡 Hint

Without -p, mkdir cannot create nested directories if parents don't exist; see step 3 explanation.

Concept Snapshot

mkdir command creates directories.
If directory exists, mkdir errors unless -p option is used.
-p creates parent directories as needed.
Syntax: mkdir [options] directory_name
Use -p for nested directories without errors.

Full Transcript

The mkdir command is used to create directories in Linux. When you run mkdir with a directory name, it creates that directory if it does not exist. If the directory already exists, mkdir shows an error unless you use the -p option. The -p option allows creating nested directories and does not error if the directory exists. For example, running 'mkdir myfolder' creates a folder named myfolder. Running it again causes an error because the folder exists. Using 'mkdir -p myfolder/subfolder' creates the subfolder inside myfolder, creating any missing parent directories as needed.

Practice

1. What does the mkdir command do in Linux?

easy

A. Deletes files from the system

B. Creates new directories (folders) to organize files

C. Lists files in a directory

D. Changes the current directory

Solution

1. Step 1: Understand the purpose of mkdir

   The mkdir command is used to create new directories (folders) in Linux.

2. Step 2: Compare with other commands

   Deleting files is done by rm, listing files by ls, and changing directories by cd.

3. Final Answer:

   Creates new directories (folders) to organize files -> Option B

4. Quick Check:

   mkdir = create folders [OK]

Hint: mkdir always makes folders, not files or lists [OK]

Common Mistakes:

• Confusing mkdir with rm or ls commands
• Thinking mkdir deletes files
• Assuming mkdir changes directories

2. Which of the following is the correct syntax to create a directory named projects?

easy

A. mkdir: projects

B. mkdir -d projects

C. mkdir projects

D. mkdir > projects

Solution

1. Step 1: Recall mkdir syntax

   The basic syntax to create a directory is mkdir directory_name. No extra symbols or options are needed for a simple directory.

2. Step 2: Evaluate options

   mkdir -d projects uses a non-existent -d flag, mkdir: projects uses invalid colon syntax, and mkdir > projects uses redirection which is incorrect here.

3. Final Answer:

   mkdir projects -> Option C

4. Quick Check:

   Simple mkdir = mkdir directory_name [OK]

Hint: Use just mkdir plus folder name to create one folder [OK]

Common Mistakes:

• Adding unnecessary flags like -d
• Using colons or symbols incorrectly
• Trying to redirect output with >

3. What will be the result of running this command?

mkdir -p home/user/docs

medium

A. Creates home, user, and docs directories if they don't exist

B. Creates only the docs directory if home/user exists

C. Shows an error because -p is invalid

D. Deletes existing home/user/docs directory

Solution

1. Step 1: Understand the -p option

   The -p option tells mkdir to create parent directories as needed without error if they already exist.

2. Step 2: Analyze the command effect

   This command creates the full path home/user/docs including any missing directories in the path.

3. Final Answer:

   Creates home, user, and docs directories if they don't exist -> Option A

4. Quick Check:

   mkdir -p = create nested folders [OK]

Hint: Use -p to make all needed folders in one go [OK]

Common Mistakes:

• Thinking -p only creates the last folder
• Assuming -p is invalid or causes errors
• Confusing mkdir with delete commands

4. You run mkdir folder1 folder2 folder3 but get an error. What is the most likely cause?

medium

A. You need to use -p to create multiple folders

B. mkdir cannot create more than one folder at a time

C. You must create folders one by one with separate commands

D. One or more folder names contain spaces without quotes

Solution

1. Step 1: Check mkdir multiple folder support

   mkdir supports creating multiple folders by listing names separated by spaces.

2. Step 2: Identify common error with spaces

   If folder names contain spaces, they must be quoted or escaped. Otherwise, mkdir treats parts as separate names causing errors.

3. Final Answer:

   One or more folder names contain spaces without quotes -> Option D

4. Quick Check:

   Spaces in names need quotes for mkdir [OK]

Hint: Quote folder names with spaces to avoid errors [OK]

Common Mistakes:

• Thinking -p is needed for multiple folders
• Believing mkdir only creates one folder at a time
• Not quoting folder names with spaces

5. You want to create a project folder structure with src, bin, and docs inside myproject in one command. Which command achieves this?

hard

A. mkdir -p myproject/src myproject/bin myproject/docs

B. mkdir myproject && mkdir src bin docs

C. mkdir -p myproject/src/bin/docs

D. mkdir myproject/src myproject/bin myproject/docs

Solution

1. Step 1: Understand nested folder creation

   Using -p allows creating parent directories and nested folders in one command without errors.

2. Step 2: Analyze each option

   mkdir myproject/src myproject/bin myproject/docs lacks -p so may fail if myproject doesn't exist. mkdir -p myproject/src myproject/bin myproject/docs correctly uses -p to create all paths. mkdir -p myproject/src/bin/docs creates nested folders incorrectly. mkdir myproject && mkdir src bin docs creates folders separately, not in one command.

3. Final Answer:

   mkdir -p myproject/src myproject/bin myproject/docs -> Option A

4. Quick Check:

   Use mkdir -p with full paths for multiple nested folders [OK]

Hint: Use mkdir -p with all paths to create nested folders at once [OK]

Common Mistakes:

• Omitting -p when parent folder doesn't exist
• Creating nested folders incorrectly as one path
• Running multiple mkdir commands instead of one