Appending to files (>>) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to append the text 'Hello' to the file named output.txt.

Bash Scripting

echo "Hello" [1] output.txt

Drag options to blanks, or click blank then click option'

A<

B>

C>>

D|

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' which overwrites the file instead of appending.

Using '<' which is for input redirection, not output.

Using '|' which pipes output to another command.

The '>>' operator appends the output to the file without overwriting existing content.

2fill in blank

medium

Complete the code to append the output of the command 'date' to the file log.txt.

Bash Scripting

date [1] log.txt

Drag options to blanks, or click blank then click option'

A|

B>>

C<

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' which overwrites the file.

Using '<' which is for input redirection.

Using '|' which sends output to another command.

Using '>>' appends the output of 'date' to log.txt without erasing existing content.

3fill in blank

hard

Fix the error in the code to append the string 'Done' to the file results.txt.

Bash Scripting

echo Done [1] results.txt

Drag options to blanks, or click blank then click option'

A>>

B<

C>

D|

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' which overwrites the file.

Using '<' which is for input redirection.

Using '|' which pipes output to another command.

The '>>' operator correctly appends the string to the file without overwriting.

4fill in blank

hard

Fill both blanks to append the output of 'ls -l' to the file directory_list.txt.

Bash Scripting

[1] [2] directory_list.txt

Drag options to blanks, or click blank then click option'

Als -l

B>

C>>

Dcat

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' which overwrites the file.

Using 'cat' instead of the listing command.

Swapping the order of command and operator.

The command 'ls -l' lists files, and '>>' appends its output to the file.

5fill in blank

hard

Fill all three blanks to append the word count of file.txt to counts.log.

Bash Scripting

[1] [2] [3] counts.log

Drag options to blanks, or click blank then click option'

Awc -w

B>>

Cfile.txt

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' which overwrites the file.

Swapping the file name and operator positions.

Using wrong command instead of 'wc -w'.

The command 'wc -w file.txt' counts words, and '>>' appends the result to counts.log.

Practice

1. What does the >> operator do in bash scripting?

easy

A. It adds new content to the end of a file without deleting existing data.

B. It deletes the file before writing new content.

C. It reads the content of a file.

D. It copies a file to another location.

Solution

1. Step 1: Understand the operator function

   The >> operator appends data to a file, meaning it adds new content at the end without removing what is already there.

2. Step 2: Compare with other operators

   Unlike > which overwrites, >> keeps existing content and adds more.

3. Final Answer:

   It adds new content to the end of a file without deleting existing data. -> Option A

4. Quick Check:

   >> appends content [OK]

Hint: Remember: double > means add, single > means replace [OK]

Common Mistakes:

• Confusing >> with > which overwrites files
• Thinking >> deletes the file first
• Assuming >> reads file content

2. Which of the following is the correct syntax to append the text "Hello" to a file named greetings.txt?

easy

A. echo Hello < greetings.txt

B. echo Hello > greetings.txt

C. echo Hello >> greetings.txt

D. echo Hello | greetings.txt

Solution

1. Step 1: Identify the append operator

   To add text to the end of a file, use >> after the command.

2. Step 2: Match syntax with the command

   echo Hello >> greetings.txt appends "Hello" to the file without deleting existing content.

3. Final Answer:

   echo Hello >> greetings.txt -> Option C

4. Quick Check:

   Use >> to append text [OK]

Hint: Use echo text >> filename to append text [OK]

Common Mistakes:

• Using single > which overwrites the file
• Using < which is for input redirection
• Using pipe | incorrectly to write to file

3. What will be the content of log.txt after running these commands?

echo "Start" > log.txt
echo "Step 1" >> log.txt
echo "Step 2" >> log.txt

medium

A. Step 1
Step 2

B. Start
Step 2

C. Start

D. Start
Step 1
Step 2

Solution

1. Step 1: Analyze the first command

   echo "Start" > log.txt creates or overwrites log.txt with "Start".

2. Step 2: Analyze the next two append commands

   Both echo "Step 1" >> log.txt and echo "Step 2" >> log.txt add lines at the end without deleting existing content.

3. Final Answer:

   Start Step 1 Step 2 -> Option D

4. Quick Check:

   First > overwrites, then >> appends [OK]

Hint: First > overwrites, then >> adds lines [OK]

Common Mistakes:

• Thinking >> overwrites file
• Ignoring newline added by echo
• Assuming only last echo remains

4. You want to append the line "Backup complete" to backup.log, but your script uses echo "Backup complete" > backup.log. What is the problem?

medium

A. The command appends but adds extra blank lines.

B. The command overwrites the file instead of appending.

C. The file backup.log will not be created.

D. The command will cause a syntax error.

Solution

1. Step 1: Understand the operator used

   The single > operator overwrites the file content, replacing it with new text.

2. Step 2: Identify correct operator for appending

   To add text without deleting existing content, >> should be used instead.

3. Final Answer:

   The command overwrites the file instead of appending. -> Option B

4. Quick Check:

   Use >> to append, not > [OK]

Hint: Use >> to append, > overwrites [OK]

Common Mistakes:

• Using > when >> is needed
• Expecting append but file is replaced
• Thinking > causes syntax error

5. You have a script that logs user actions to actions.log. You want to ensure the file is created if missing and new actions are added without deleting old logs. Which command correctly appends the text "User logged in" to the file?

hard

A. echo "User logged in" >> actions.log

B. echo "User logged in" > actions.log

C. cat "User logged in" >> actions.log

D. echo "User logged in" < actions.log

Solution

1. Step 1: Confirm file creation and appending

   The >> operator appends text and creates the file if it does not exist.

2. Step 2: Validate command correctness

   echo "User logged in" >> actions.log appends the message correctly without deleting old logs.

3. Final Answer:

   echo "User logged in" >> actions.log -> Option A

4. Quick Check:

   >> appends and creates file if missing [OK]

Hint: Use echo text >> file to append and create file if missing [OK]

Common Mistakes:

• Using > which overwrites logs
• Using < which is input redirection
• Using cat incorrectly to append text