stdout redirection (>, >>) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the content of the file after this command?

Assume file.txt initially contains:

Hello

What will be the content of file.txt after running:

echo "World" > file.txt

Linux CLI

echo "World" > file.txt

A Hello

B Hello\nWorld

C World

D World\nHello

💡 Hint

The single > operator overwrites the file content.

The > operator replaces the entire content of the file with the new output. So the file will only contain "World".

💻 Command Output

intermediate

What will be the content of the file after appending?

Assume file.txt initially contains:

Line1

What will be the content of file.txt after running:

echo "Line2" >> file.txt

Linux CLI

echo "Line2" >> file.txt

A Line2

B Line1\nLine2

C Line1

D Line2\nLine1

💡 Hint

The >> operator adds the output to the end of the file.

The >> operator appends the output to the existing file content, so the file will have both lines.

💻 Command Output

advanced

What is the output of this command sequence?

Given an empty file log.txt, what will be the content after running these commands?

echo "Start" > log.txt
 echo "Middle" >> log.txt
 echo "End" > log.txt

Linux CLI

echo "Start" > log.txt
 echo "Middle" >> log.txt
 echo "End" > log.txt

A End

B Start\nMiddle

C Start\nMiddle\nEnd

D Middle\nEnd

💡 Hint

The last command overwrites the file again.

The first command writes "Start", the second appends "Middle", but the last command overwrites the file with "End" only.

💻 Command Output

advanced

What error or output occurs here?

What happens if you run this command when readonly.txt is a read-only file?

echo "New content" > readonly.txt

Linux CLI

echo "New content" > readonly.txt

A Permission denied error

B New content is written to the file

C File is created with new content

D No output, command silently fails

💡 Hint

You need write permission to overwrite a file.

If the file is read-only, the shell cannot overwrite it and will show a permission denied error.

🧠 Conceptual

expert

How many lines will the file contain after this script?

Consider this script run in an empty directory:

for i in 1 2 3; do
  echo "Line $i" >> file.txt
  echo "Overwrite $i" > file.txt
 done

How many lines will file.txt have after the loop finishes?

Linux CLI

for i in 1 2 3; do
  echo "Line $i" >> file.txt
  echo "Overwrite $i" > file.txt
 done

A 0

B 3

C 6

D 1

💡 Hint

Each loop overwrites the file after appending.

Each loop first appends a line, then immediately overwrites the file with one line. After 3 loops, only the last overwrite remains, so the file has 1 line.