tar with compression (-z, -j, -J) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this tar command?

You run this command in a directory containing a file named file.txt with the text Hello inside:

tar -czf archive.tar.gz file.txt && tar -tzf archive.tar.gz

What will be the output?

Linux CLI

tar -czf archive.tar.gz file.txt && tar -tzf archive.tar.gz

A file.txt

B file.txt\narchive.tar.gz

C archive.tar.gz

D Error: Cannot list compressed archive

💡 Hint

The -t option lists files inside the archive. The -z option means gzip compression.

The command creates a gzip compressed archive named archive.tar.gz containing file.txt. The tar -tzf command lists the files inside the gzip compressed archive, which is just file.txt.

💻 Command Output

intermediate

What error does this command produce?

You run this command:

tar -cjf archive.tar.bz2 file.txt && tar -tzf archive.tar.bz2

What error message will you see?

Linux CLI

tar -cjf archive.tar.bz2 file.txt && tar -tzf archive.tar.bz2

A tar: This does not look like a tar archive

B No such file or directory

C file.txt

D archive.tar.bz2

💡 Hint

The -j option compresses with bzip2, but the -z option tries to decompress with gzip.

The archive is compressed with bzip2 (-j), but the listing command uses -z which expects gzip compression. This mismatch causes tar to fail with the error 'This does not look like a tar archive'.

📝 Syntax

advanced

Which command correctly creates an xz compressed tar archive?

You want to create a tar archive compressed with xz compression named archive.tar.xz containing the folder data. Which command is correct?

A tar -cZf archive.tar.xz data

B tar -cJf archive.tar.xz data

C tar -cjf archive.tar.xz data

D tar -czf archive.tar.xz data

💡 Hint

The -J option is for xz compression.

The -J option tells tar to use xz compression. Other options are for different compressions: -z gzip, -j bzip2, -Z compress (rare).

🚀 Application

advanced

How to extract a bzip2 compressed archive to a specific folder?

You have a bzip2 compressed tar archive named backup.tar.bz2. You want to extract its contents into the folder /tmp/restore. Which command will do this correctly?

A tar -xvf backup.tar.bz2 /tmp/restore

B tar -xzf backup.tar.bz2 -C /tmp/restore

C tar -xJf backup.tar.bz2 -C /tmp/restore

D tar -xjf backup.tar.bz2 -C /tmp/restore

💡 Hint

Use -j for bzip2 and -C to specify extraction directory.

The -j option decompresses bzip2 archives. The -C option tells tar to change to the specified directory before extracting files.

🔧 Debug

expert

Why does this tar extraction fail with 'Cannot open: No such file or directory'?

You run this command:

tar -xzf archive.tar.bz2

and get the error:

tar: archive.tar.bz2: Cannot open: No such file or directory

What is the most likely cause?

Linux CLI

tar -xzf archive.tar.bz2

A The archive is corrupted

B The -z option cannot be used with .bz2 files

C The file archive.tar.bz2 does not exist in the current directory

D You need to run the command as root

💡 Hint

Check if the file is present in the folder you are running the command from.

The error means the file archive.tar.bz2 is not found in the current directory. The -z option mismatch would cause a different error. Running as root or corruption would not cause 'No such file or directory'.

Practice

1. Which option correctly describes the -z flag when used with the tar command?

easy

A. It compresses the archive using gzip.

B. It compresses the archive using bzip2.

C. It compresses the archive using xz.

D. It creates an uncompressed archive.

Solution

1. Step 1: Understand the tar compression flags

   The -z flag tells tar to use gzip compression.

2. Step 2: Match the flag to the compression type

   -z is for gzip, -j for bzip2, and -J for xz compression.

3. Final Answer:

   It compresses the archive using gzip. -> Option A

4. Quick Check:

   -z means gzip compression [OK]

Hint: Remember: z = gzip, j = bzip2, J = xz [OK]

Common Mistakes:

• Confusing -z with -j or -J
• Thinking -z creates uncompressed archive
• Mixing compression types

2. Which of the following is the correct syntax to create a bzip2 compressed tar archive named backup.tar.bz2 from the directory data?

easy

A. tar -cJf backup.tar.bz2 data

B. tar -czf backup.tar.bz2 data

C. tar -cjf backup.tar.bz2 data

D. tar -cf backup.tar.bz2 data

Solution

1. Step 1: Identify the compression flag for bzip2

   The -j flag is used for bzip2 compression.

2. Step 2: Check the full command syntax

   tar -cjf backup.tar.bz2 data creates a bzip2 compressed archive named backup.tar.bz2 from data.

3. Final Answer:

   tar -cjf backup.tar.bz2 data -> Option C

4. Quick Check:

   -j means bzip2 compression [OK]

Hint: Use -j for bzip2 compression in tar commands [OK]

Common Mistakes:

• Using -z instead of -j for bzip2
• Forgetting the 'f' flag for filename
• Mixing compression flags and extensions

3. What will be the output of the following command if the directory project contains files and subdirectories?

tar -cJf project.tar.xz project

medium

A. Creates an uncompressed tar archive named project.tar.xz

B. Creates an xz compressed tar archive named project.tar.xz

C. Creates a gzip compressed tar archive named project.tar.xz

D. Throws an error because -J is invalid

Solution

1. Step 1: Understand the -J flag

   The -J flag tells tar to use xz compression.

2. Step 2: Analyze the command output

   The command creates a compressed archive named project.tar.xz using xz compression from the project directory.

3. Final Answer:

   Creates an xz compressed tar archive named project.tar.xz -> Option B

4. Quick Check:

   -J means xz compression [OK]

Hint: Remember: -J compresses with xz, matching .tar.xz files [OK]

Common Mistakes:

• Thinking -J is invalid
• Confusing -J with -z or -j
• Assuming no compression happens

4. You run the command tar -cjf archive.tar.gz folder but get an error. What is the likely cause?

medium

A. The -f flag is missing

B. The -c flag is missing

C. The -j flag cannot be combined with .tar.gz extension

D. The folder does not exist

Solution

1. Step 1: Verify the flags and syntax

   The command has all required flags: -c for create, -j for bzip2, -f for file.

2. Step 2: Identify the likely error source

   tar will error if the source folder does not exist, typically with "Cannot stat: No such file or directory".

3. Final Answer:

   The folder does not exist -> Option D

4. Quick Check:

   Check source exists before tar [OK]

Hint: Always verify source directory exists before archiving [OK]

Common Mistakes:

• Assuming flag or extension issues
• Overlooking if folder exists
• Focusing on compression mismatch

5. You want to create a compressed archive of the logs directory using the best compression ratio available with tar. Which command should you use?

hard

A. tar -cJf logs.tar.xz logs

B. tar -cjf logs.tar.bz2 logs

C. tar -czf logs.tar.gz logs

D. tar -cf logs.tar logs

Solution

1. Step 1: Identify compression types and their ratios

   Gzip (-z) is fast but less compressed, bzip2 (-j) is better, and xz (-J) offers the best compression ratio.

2. Step 2: Choose the best compression flag

   Using -cJf creates an xz compressed archive, which has the best compression ratio.

3. Final Answer:

   tar -cJf logs.tar.xz logs -> Option A

4. Quick Check:

   Best compression = xz = -J flag [OK]

Hint: Use -J for best compression with tar [OK]

Common Mistakes:

• Choosing gzip or bzip2 for best compression
• Forgetting compression flag
• Using uncompressed tar by mistake