head and tail in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of head command with line count

What is the output of the command head -n 3 sample.txt if sample.txt contains these lines?

Line1
Line2
Line3
Line4
Line5

Linux CLI

head -n 3 sample.txt

A

Line4
Line5

B

Line3
Line4
Line5

C

Line1
Line2
Line3
Line4
Line5

D

Line1
Line2
Line3

💡 Hint

head shows the first lines of a file.

The head -n 3 command prints the first 3 lines of the file.

💻 Command Output

intermediate

Output of tail command with byte count

What is the output of tail -c 5 sample.txt if sample.txt contains exactly HelloWorld?

Linux CLI

tail -c 5 sample.txt

A HelloWorld

B Hello

C World

D dlroW

💡 Hint

tail -c shows last bytes, counting characters.

The last 5 characters of 'HelloWorld' are 'World'.

🔧 Debug

advanced

Effect of tail -n with negative number

You run tail -n -3 sample.txt. What happens?
Choose the correct statement.

Linux CLI

tail -n -3 sample.txt

A The command syntax is correct; no error should occur.

B Negative numbers are not allowed with -n option in tail.

C The -n option requires a positive integer or zero.

D The file sample.txt does not exist.

💡 Hint

Check tail manual for allowed values of -n. Negative numbers indicate 'all but last N lines'.

The command syntax is incorrect; tail does not accept negative numbers with -n option. It will produce an error.

🧠 Conceptual

advanced

Combining head and tail to get middle lines

You want to extract lines 4 to 6 from a file named data.txt. Which command correctly does this?

A head -n 6 data.txt | tail -n 3

B tail -n 6 data.txt | head -n 3

C tail -n 3 data.txt | head -n 6

D head -n 3 data.txt | tail -n 6

💡 Hint

Use head to get first 6 lines, then tail to get last 3 of those.

head -n 6 gets first 6 lines; tail -n 3 extracts lines 4,5,6 from those.

🚀 Application

expert

Script to monitor last 10 lines of a growing log file

You want to write a script that continuously shows the last 10 lines of app.log as it grows, updating in real-time. Which command achieves this?

A tail -f -n 10 app.log

B head -f -n 10 app.log

C tail -n 10 app.log

D head -n 10 app.log

💡 Hint

Use tail with follow option to watch file growth.

tail -f -n 10 shows last 10 lines and updates as file grows.