du (disk usage by directory) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this du command?

You run the command du -sh /var/log on a Linux system. What does the output represent?

Linux CLI

du -sh /var/log

A The total disk space used by the /var/log directory and all its contents, shown in a human-readable format.

B The free disk space available on the partition containing /var/log.

C The number of files inside /var/log directory.

D The size of the largest file inside /var/log.

💡 Hint

Think about what the options -s and -h mean in the du command.

The -s option summarizes the total size of the directory, and -h makes the output human-readable (like KB, MB). So the output shows total disk usage of /var/log.

💻 Command Output

intermediate

What does this command output?

You run du -h --max-depth=1 /home/user. What will the output show?

Linux CLI

du -h --max-depth=1 /home/user

A Only the total disk usage of /home/user without details.

B Disk usage of all files inside /home/user recursively, one line per file.

C Disk usage of /home/user and each of its immediate subdirectories, in human-readable form.

D Disk usage of /home/user but excluding hidden files.

💡 Hint

The --max-depth=1 limits how deep du reports.

The --max-depth=1 option tells du to show sizes for the directory and its immediate children only, not deeper nested folders.

🔧 Debug

advanced

Why does this du command fail?

You try to run du -h --maxdepth=1 /etc but get an error. What is the cause?

Linux CLI

du -h --maxdepth=1 /etc

A The option should be spelled <code>--max-depth</code> with a hyphen, not <code>--maxdepth</code>.

B The directory /etc does not exist.

C The <code>-h</code> option cannot be combined with <code>--maxdepth</code>.

D You need root permissions to run du on /etc.

💡 Hint

Check the spelling of the option carefully.

The correct option is --max-depth with a hyphen. Using --maxdepth causes an unrecognized option error.

🚀 Application

advanced

How to find the top 3 largest subdirectories in /var?

You want to list the three largest subdirectories inside /var by disk usage. Which command will do this?

A du -sh /var/* | sort -h | tail -n 3

B du -h /var | sort -h | head -n 3

C du -sh /var | sort -hr | head -n 3

D du -h --max-depth=1 /var | sort -hr | head -n 3

💡 Hint

Use du with max-depth to get sizes of immediate subdirectories, then sort and pick top 3.

du -h --max-depth=1 /var lists sizes of /var and its immediate subdirectories. Sorting numerically in reverse order with sort -hr puts largest first. head -n 3 picks top three.

🧠 Conceptual

expert

What is the effect of using du -b compared to du -h?

You run du -b /tmp and du -h /tmp. What is the difference in their outputs?

A <code>du -b</code> shows sizes in bits, <code>du -h</code> shows sizes in bytes.

B <code>du -b</code> shows disk usage in bytes (exact number), while <code>du -h</code> shows sizes in human-readable units like KB or MB.

C <code>du -b</code> shows sizes rounded to nearest KB, <code>du -h</code> shows exact bytes.

D <code>du -b</code> shows block counts, <code>du -h</code> shows bytes.

💡 Hint

Think about what the -b and -h options mean for size units.

-b means show size in bytes (exact count). -h means human-readable format with units like KB, MB, GB for easier reading.