Here documents (<<EOF) in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this here document script?

Consider the following Bash script using a here document. What will it print when run?

Bash Scripting

cat <<EOF
Hello
World
EOF

A

Hello
World

B Hello World

C cat: EOF: No such file or directory

D EOF\nHello\nWorld

💡 Hint

The here document sends the lines between <

The cat command receives the lines 'Hello' and 'World' as input and prints them exactly, each on its own line.

💻 Command Output

intermediate

What happens if the delimiter is quoted in a here document?

What will this script output? cat <<'EOF' $HOME EOF

Bash Scripting

cat <<'EOF'
$HOME
EOF

A /home/username

B Syntax error near unexpected token `EOF'

C $HOME

D EOF

💡 Hint

Quoting the delimiter disables variable expansion inside the here document.

When the delimiter is quoted, the content is treated literally, so $HOME is not expanded.

🔧 Debug

advanced

Why does this here document script fail to run?

This script is intended to print a multi-line message, but it fails with a syntax error. Identify the cause. cat <

Bash Scripting

cat <<EOF
Hello
World

A cat command is misspelled

B Missing closing delimiter 'EOF' causes syntax error

C Here document delimiter must be quoted

D EOF must be uppercase

💡 Hint

The shell expects the ending delimiter to close the here document.

The here document must end with the exact delimiter on a line by itself. Missing it causes a syntax error.

🚀 Application

advanced

Which script correctly uses a here document to create a file with variable content?

You want to create a file named 'greeting.txt' containing the text 'Hello, Alice!'. The variable NAME='Alice' is set. Which script does this correctly?

Bash Scripting

NAME='Alice'
# Choose the correct script

A

cat <<EOF > greeting.txt
Hello, $NAME!
EOF

B

cat <<'EOF' > greeting.txt
Hello, $NAME!
EOF

C

cat <<EOF > greeting.txt
Hello, NAME!
EOF

D

cat <<EOF > greeting.txt
Hello, \$NAME!
EOF

💡 Hint

Variable expansion happens only if the delimiter is unquoted.

Option A expands $NAME to 'Alice'. Option A treats $NAME literally. Option A escapes the dollar sign, so no expansion. Option A prints 'NAME' literally.

🧠 Conceptual

expert

How does the shell treat leading tabs in here documents with <<-?

What is the effect of using <<-EOF instead of <

Bash Scripting

cat <<-EOF
	Hello
	World
EOF

A The here document is treated as a comment

B Leading spaces before content lines are stripped

C The here document delimiter must be quoted

D Leading tabs before content lines are stripped

💡 Hint

The dash after << enables a special behavior with tabs.

Using <<- allows the shell to ignore leading tab characters in the here document lines, making indentation cleaner.