tar (create and extract archives) in Linux CLI - Mini Project: Build & Apply

Using tar to Create and Extract Archives

📖 Scenario: You have a folder with some important files. You want to bundle them into one archive file to save space or share easily. Later, you want to open that archive to get the files back.

🎯 Goal: Learn how to use the tar command to create an archive file from multiple files and then extract the files back from the archive.

📋 What You'll Learn

Create a tar archive from multiple files

Use a variable to store the archive file name

Extract files from the tar archive

Display the list of files extracted

💡 Why This Matters

🌍 Real World

Archiving files into a single file helps in backup, sharing, and saving disk space. The tar command is widely used in Linux systems for these tasks.

💼 Career

Knowing how to create and extract tar archives is essential for system administrators, developers, and anyone working with Linux servers or managing files efficiently.

1

Create sample files

Create three empty files named file1.txt, file2.txt, and file3.txt using the touch command.

Linux CLI

# Create three empty files named file1.txt, file2.txt, and file3.txt
# Your code here

Hint

Use touch followed by the file names separated by spaces.

2

Set archive file name variable

Create a variable called archive_name and set it to myfiles.tar.

Linux CLI

touch file1.txt file2.txt file3.txt
# Create a variable archive_name and set it to myfiles.tar
# Your code here

Hint

Use archive_name=myfiles.tar without spaces around the equals sign.

3

Create the tar archive

Use the tar command with options -cf to create an archive named by $archive_name containing file1.txt, file2.txt, and file3.txt.

Linux CLI

touch file1.txt file2.txt file3.txt
archive_name=myfiles.tar
# Create a tar archive named $archive_name with the three files
# Your code here

Hint

Use tar -cf $archive_name file1.txt file2.txt file3.txt to create the archive.

4

Extract and list files from the archive

Use the tar command with options -xf to extract files from $archive_name. Then use ls to list the extracted files.

Linux CLI

touch file1.txt file2.txt file3.txt
archive_name=myfiles.tar
tar -cf $archive_name file1.txt file2.txt file3.txt
# Extract files from $archive_name and list them
# Your code here

Hint

Use tar -xf $archive_name to extract and ls file1.txt file2.txt file3.txt to list the files.

Practice

1. What does the tar -cvf archive.tar folder/ command do?

easy

A. Extracts files from archive.tar into the folder directory

B. Compresses the folder directory using gzip

C. Creates a tar archive named archive.tar containing the folder directory

D. Lists the contents of archive.tar without extracting

Solution

1. Step 1: Understand the flags used

   The -c flag means create an archive, -v means verbose (show progress), and -f specifies the archive file name.

2. Step 2: Analyze the command effect

   The command creates a new archive file named archive.tar containing the contents of the folder/ directory.

3. Final Answer:

   Creates a tar archive named archive.tar containing the folder directory -> Option C

4. Quick Check:

   tar -cvf = create archive [OK]

Hint: -c means create archive, -f specifies filename [OK]

Common Mistakes:

• Confusing -c (create) with -x (extract)
• Thinking -v compresses files
• Assuming it extracts files instead of creating

2. Which of the following is the correct syntax to extract a gzip compressed tar archive named backup.tar.gz?

easy

A. tar -xvzf backup.tar.gz

B. tar -xvf backup.tar.gz

C. tar -cvf backup.tar.gz

D. tar -czf backup.tar.gz

Solution

1. Step 1: Identify extraction and compression flags

   -x extracts, -v shows progress, -z handles gzip compression, and -f specifies the file.

2. Step 2: Match flags to the command

   To extract a gzip compressed archive, use tar -xvzf filename. tar -xvzf backup.tar.gz matches this syntax.

3. Final Answer:

   tar -xvzf backup.tar.gz -> Option A

4. Quick Check:

   Extract gzip archive = -xvzf [OK]

Hint: -xvzf extracts gzip compressed tar files [OK]

Common Mistakes:

• Omitting -z when extracting gzip archives
• Using -c (create) instead of -x (extract)
• Confusing -v (verbose) as mandatory

3. What will be the output of the command tar -tvf archive.tar if archive.tar contains files file1.txt and file2.txt?

medium

A. Shows an error because -t cannot be combined with -v

B. Extracts file1.txt and file2.txt to current directory

C. Creates a new archive named archive.tar

D. Lists file1.txt and file2.txt with details without extracting

Solution

1. Step 1: Understand the flags

   -t lists contents of an archive, -v shows details, and -f specifies the archive file.

2. Step 2: Predict the command output

   The command lists the files inside archive.tar with details, without extracting them.

3. Final Answer:

   Lists file1.txt and file2.txt with details without extracting -> Option D

4. Quick Check:

   -t lists contents, -v shows details [OK]

Hint: -t lists archive contents, -v adds details [OK]

Common Mistakes:

• Thinking it extracts files instead of listing
• Assuming -t and -v cannot be combined
• Confusing -t with -x

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

medium

A. The order of flags is incorrect; -z must come before -c

B. The folder/ directory does not exist

C. The -f flag must be last and followed by the filename

D. You cannot combine -v and -z flags

Solution

1. Step 1: Verify command syntax

   The flags -c (create), -v (verbose), -z (gzip), -f archive.tar.gz are correct, with filename immediately after -f.

2. Step 2: Determine error cause

   The syntax is valid, so the likely cause is that folder/ does not exist, causing a "Cannot stat: No such file or directory" error.

3. Final Answer:

   The folder/ directory does not exist -> Option B

4. Quick Check:

   tar create error = missing source directory [OK]

Hint: tar create errors usually from missing source files/directories [OK]

Common Mistakes:

• Assuming flag order syntax error
• Overlooking if source directory exists
• Confusing with permission issues

5. You want to create a compressed archive of the project/ folder, but exclude all .log files inside it. Which command achieves this?

hard

A. tar -czvf project.tar.gz --exclude='*.log' project/

B. tar -czvf project.tar.gz project/ --exclude='*.log'

C. tar -cvzf project.tar.gz project/ --exclude='*.log'

D. tar -xvzf project.tar.gz --exclude='*.log' project/

Solution

1. Step 1: Understand exclusion and compression flags

   The --exclude='*.log' option excludes files matching the pattern. -c creates, -z compresses with gzip, -v shows progress, and -f specifies the archive filename.

2. Step 2: Check correct flag order and placement

   The exclude option must come before the folder argument. tar -czvf project.tar.gz --exclude='*.log' project/ correctly places --exclude='*.log' before project/ and uses correct flags.

3. Final Answer:

   tar -czvf project.tar.gz --exclude='*.log' project/ -> Option A

4. Quick Check:

   Exclude before folder, use -czvf for compressed archive [OK]

Hint: Put --exclude before folder, use -czvf to create compressed archive [OK]

Common Mistakes:

• Placing --exclude after folder argument
• Using -x (extract) instead of -c (create)
• Mixing flag order or misspelling exclude