cat (display file contents) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this command?

You have a file named example.txt with the following content:

Hello
World

What will be the output of the command cat example.txt?

Linux CLI

cat example.txt

A

Hello
World

B Hello World

C Hello\nWorld

D example.txt

💡 Hint

The cat command prints the file content exactly as it is.

The cat command outputs the content of the file preserving line breaks. So it prints 'Hello' on the first line and 'World' on the second line.

💻 Command Output

intermediate

What happens when you use cat on multiple files?

You have two files:
file1.txt contains:

Apple

file2.txt contains:

Banana

What is the output of cat file1.txt file2.txt?

Linux CLI

cat file1.txt file2.txt

A AppleBanana

B Apple\nBanana

C

Apple
Banana

D file1.txt file2.txt

💡 Hint

The cat command concatenates files and prints their contents in order.

The command prints the content of file1.txt followed by the content of file2.txt, preserving line breaks.

💻 Command Output

advanced

What is the output of this command with a non-existent file?

What happens when you run cat missing.txt if missing.txt does not exist?

Linux CLI

cat missing.txt

A No output, command succeeds silently

B Syntax error

C missing.txt

D cat: missing.txt: No such file or directory

💡 Hint

Try to think what happens when a file is not found.

The cat command prints an error message to standard error if the file does not exist.

💻 Command Output

advanced

What is the output of this command with input redirection?

What will be the output of cat < file.txt if file.txt contains:

Line1
Line2

?

Linux CLI

cat < file.txt

A

Line1
Line2

B Line1\nLine2

C Line1 Line2

D Error: invalid syntax

💡 Hint

Input redirection feeds the file content to the command as standard input.

Using input redirection, cat reads from the file and outputs its content preserving line breaks.

🧠 Conceptual

expert

How many lines will this command output?

You run the command cat fileA.txt fileB.txt | wc -l.

fileA.txt has 3 lines, fileB.txt has 5 lines.

What is the output number?

A 3

B 8

C 5

D 1

💡 Hint

The pipe sends combined output of both files to wc -l which counts lines.

The cat command concatenates both files, so total lines are 3 + 5 = 8. The wc -l counts these lines.