mkdir (create directories) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this mkdir command?

You run the command mkdir -p /tmp/testdir/subdir on a Linux system. What happens if /tmp/testdir does not exist?

Linux CLI

mkdir -p /tmp/testdir/subdir

A Both /tmp/testdir and /tmp/testdir/subdir directories are created without error.

B Only /tmp/testdir/subdir is created; /tmp/testdir must exist first or it errors.

C The command fails with a permission denied error.

D The command creates a file named subdir inside /tmp/testdir.

💡 Hint

The -p option helps create parent directories if missing.

The -p flag tells mkdir to create parent directories as needed. So if /tmp/testdir doesn't exist, it will be created first, then subdir inside it.

💻 Command Output

intermediate

What error does this mkdir command produce?

You run mkdir /root/newdir as a normal user (not root). What is the expected output?

Linux CLI

mkdir /root/newdir

A mkdir: invalid option -- 'r'

B Directory /root/newdir created successfully.

C mkdir: missing operand

D mkdir: cannot create directory ‘/root/newdir’: Permission denied

💡 Hint

Normal users usually cannot write inside /root directory.

The /root directory is owned by root user only. Normal users lack permission to create directories there, so mkdir fails with a permission denied error.

📝 Syntax

advanced

Which mkdir command creates multiple directories at once?

You want to create three directories named dir1, dir2, and dir3 in your current folder with one command. Which option is correct?

A mkdir dir1 dir2 dir3

B mkdir -p dir1,dir2,dir3

C mkdir dir1; mkdir dir2; mkdir dir3

D mkdir -m dir1 dir2 dir3

💡 Hint

mkdir can take multiple directory names separated by spaces.

The mkdir command accepts multiple directory names separated by spaces to create them all at once. Option A does this correctly.

💻 Command Output

advanced

What is the effect of this mkdir command with -m option?

You run mkdir -m 700 secret. What are the permissions of the created directory?

Linux CLI

mkdir -m 700 secret

A The directory 'secret' is created with default permissions 755.

B The command fails with an invalid mode error.

C The directory 'secret' is created with permissions rwx------ (only owner can read, write, execute).

D The directory 'secret' is created with permissions rwxrwxrwx.

💡 Hint

The -m option sets the permission mode of the new directory.

The -m 700 option sets permissions so only the owner has read, write, and execute rights. Others have no permissions.

🚀 Application

expert

How many directories are created by this command?

You run mkdir -p /tmp/a/b/c /tmp/a/d/e. How many new directories are created if none of these exist?

Linux CLI

mkdir -p /tmp/a/b/c /tmp/a/d/e

A 2 directories: /tmp/a/b/c and /tmp/a/d/e only

B 5 directories: /tmp/a, /tmp/a/b, /tmp/a/b/c, /tmp/a/d, /tmp/a/d/e

C 3 directories: /tmp/a/b/c, /tmp/a/d/e, /tmp/a

D 6 directories: /tmp, /tmp/a, /tmp/a/b, /tmp/a/b/c, /tmp/a/d, /tmp/a/d/e

💡 Hint

The -p option creates all missing parent directories for each path.

The command creates /tmp/a first, then /tmp/a/b, then /tmp/a/b/c for the first path. For the second path, /tmp/a/d and /tmp/a/d/e are created. /tmp exists already, so not counted.

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