bzip2 and xz compression in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of bzip2 compression command

What is the output of the following command sequence on a file named example.txt containing the text "hello world"?

cat example.txt | bzip2 > example.txt.bz2 && bzip2 -d -c example.txt.bz2

Linux CLI

echo 'hello world' > example.txt
cat example.txt | bzip2 > example.txt.bz2 && bzip2 -d -c example.txt.bz2

A

bzip2: (stdin) is not a valid bzip2 file

B

hello world.bz2

C

hello world

D

example.txt.bz2

💡 Hint

Think about what the bzip2 -d -c command does with the compressed file.

The command compresses the content of example.txt using bzip2 and writes it to example.txt.bz2. Then, bzip2 -d -c decompresses the compressed file and outputs the original content to standard output, which is 'hello world'.

💻 Command Output

intermediate

Comparing xz and bzip2 compression sizes

Given a file data.txt with repetitive content, which command will most likely produce the smallest compressed file size?

A xz -z data.txt

B bzip2 -z data.txt

C cat data.txt > data.txt.xz

D gzip -z data.txt

💡 Hint

Consider which compression tool generally achieves better compression ratios on repetitive data.

The xz tool typically compresses better than bzip2 and gzip on repetitive data, producing smaller files.

🔧 Debug

advanced

Why does this bzip2 command fail?

You run the command bzip2 -d example.txt.bz2 but get the error: bzip2: Can't decompress file: No such file or directory. The file example.txt.bz2 exists in your current directory. What is the most likely cause?

Linux CLI

bzip2 -d example.txt.bz2

A You do not have read permission on the file

B The file is actually compressed with xz, not bzip2

C The file is corrupted and cannot be decompressed

D You are running the command in a different directory than where the file is located

💡 Hint

Check your current directory and the file location carefully.

The error indicates the file cannot be found. If the file exists but the command says it does not, you are likely not in the directory where the file is located.

🧠 Conceptual

advanced

Difference in compression options between bzip2 and xz

Which statement correctly describes a difference between bzip2 and xz compression tools?

A <code>xz</code> supports higher compression levels and multi-threading, <code>bzip2</code> does not

B <code>bzip2</code> compresses faster and produces smaller files than <code>xz</code>

C <code>bzip2</code> supports multi-threaded compression by default, <code>xz</code> does not

D <code>xz</code> cannot decompress files compressed by <code>bzip2</code>

💡 Hint

Think about modern compression features and performance.

xz supports higher compression levels and multi-threaded compression, making it more flexible and often more efficient than bzip2.

🚀 Application

expert

Automate compression and decompression with error handling

You want to write a shell script that compresses a file using xz and then decompresses it back, printing the decompressed content. The script should check if the compression succeeded before decompressing. Which script snippet correctly implements this?

A xz file.txt && xz -d -c file.txt.xz

B xz file.txt; if [ $? -eq 0 ]; then xz -d -c file.txt.xz; fi

C xz file.txt || echo 'Compression failed'; xz -d -c file.txt.xz

D xz file.txt && echo 'Compression done'; xz -d -c file.txt.xz

💡 Hint

Use shell conditional statements to check command success.

Option B uses the exit status ($?) of the compression command to decide if decompression should run, ensuring decompression only happens if compression succeeded.