Uppercase and lowercase conversion in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to convert the variable 'text' to uppercase using parameter expansion.

Bash Scripting

echo "$[1]"

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

Atext^^

Btext,,

Ctext^

Dtext,,,

Attempts:

3 left

💡 Hint

Common Mistakes

Using single caret (^) converts only the first character.

Using double commas (,,) converts to lowercase instead.

Adding extra commas or carets causes syntax errors.

Using '${text^^}' converts all characters in 'text' to uppercase in bash parameter expansion.

2fill in blank

medium

Complete the code to convert the variable 'text' to lowercase using parameter expansion.

Bash Scripting

echo "$[1]"

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

Atext,,

Btext^^

Ctext^

Dtext,,,

Attempts:

3 left

💡 Hint

Common Mistakes

Using double carets (^^) converts to uppercase instead.

Using single caret (^) converts only the first character.

Adding extra commas causes syntax errors.

Using '${text,,}' converts all characters in 'text' to lowercase in bash parameter expansion.

3fill in blank

hard

Fix the error in the code to convert only the first character of 'text' to uppercase.

Bash Scripting

echo "$[1]"

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

Atext^^

Btext^

Ctext,

Dtext,,

Attempts:

3 left

💡 Hint

Common Mistakes

Using double carets (^^) converts all letters, not just the first.

Using double commas (,,) converts to lowercase.

Using a comma alone is invalid syntax.

Using '${text^}' converts only the first character of 'text' to uppercase in bash parameter expansion.

4fill in blank

hard

Fill both blanks to convert the variable 'word' to lowercase and then print it.

Bash Scripting

lowercase_word="$[1]"
echo "$[2]"

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

Aword,,

Bword^^

Clowercase_word

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase conversion instead of lowercase.

Printing the original variable instead of the lowercase one.

Mixing variable names causing undefined variable errors.

First, '${word,,}' converts 'word' to lowercase and stores it in 'lowercase_word'. Then, 'echo ${lowercase_word}' prints it.

5fill in blank

hard

Fill all three blanks to create a script that reads input into 'input_text', converts it to uppercase, and prints it.

Bash Scripting

read -p "Enter text: " [1]
uppercase_text="$[2]"
echo "$[3]"

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

Ainput_text

Binput_text^^

Cuppercase_text

Dinput_text,,

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase conversion instead of uppercase.

Printing the original input variable instead of the uppercase one.

Forgetting to assign the read input to a variable.

The script reads user input into 'input_text', converts it to uppercase with '${input_text^^}', stores in 'uppercase_text', then prints it.

Practice

1. In bash scripting, which syntax converts the value of a variable name to all uppercase letters?

easy

A. Using uppercase(name)

B. Using ${name,,}

C. Using ${name^^}

D. Using toUpperCase(name)

Solution

1. Step 1: Understand bash variable expansion for case conversion

   Bash supports ${variable^^} to convert all letters in variable to uppercase.

2. Step 2: Compare options with bash syntax

   Using ${name^^} uses ${name^^}, which is the correct bash syntax. Using ${name,,} converts to lowercase, and options C and D are not valid bash syntax.

3. Final Answer:

   Using ${name^^} -> Option C

4. Quick Check:

   Uppercase conversion = ${variable^^} [OK]

Hint: Use ${variable^^} to uppercase text in bash [OK]

Common Mistakes:

• Confusing uppercase and lowercase syntax
• Using non-bash functions like toUpperCase()
• Forgetting the double caret ^^

2. Which of the following is the correct syntax to convert the variable text to lowercase in bash?

easy

A. echo ${text,,}

B. echo ${text^^}

C. echo ${text^}

D. echo ${text,}

Solution

1. Step 1: Recall lowercase conversion syntax in bash

   To convert all letters to lowercase, bash uses ${variable,,}.

2. Step 2: Analyze each option

   echo ${text,,} uses ${text,,} which converts all letters to lowercase. echo ${text^^} converts to uppercase, C and D convert only the first letter.

3. Final Answer:

   echo ${text,,} -> Option A

4. Quick Check:

   Lowercase conversion = ${variable,,} [OK]

Hint: Use ${variable,,} to lowercase all letters in bash [OK]

Common Mistakes:

• Using single comma instead of double for all letters
• Mixing uppercase and lowercase syntax
• Confusing ^ and , operators

3. What is the output of the following bash script?

word="HelloWorld"
echo ${word,,}

medium

A. helloworld

B. helloWorld

C. HelloWorld

D. HELLOWORLD

Solution

1. Step 1: Understand the variable and conversion

   The variable word contains "HelloWorld". The expression ${word,,} converts all letters to lowercase.

2. Step 2: Apply lowercase conversion

   Converting "HelloWorld" to lowercase results in "helloworld".

3. Final Answer:

   helloworld -> Option A

4. Quick Check:

   Lowercase conversion of HelloWorld = helloworld [OK]

Hint: Lowercase all letters with ${variable,,} [OK]

Common Mistakes:

• Expecting only first letter to change
• Confusing uppercase and lowercase syntax
• Ignoring case conversion operator

4. The following bash script is intended to convert input to uppercase, but it does not work as expected:

input="bashScript"
echo $input^^

What is the error?

medium

A. Variable name is incorrect

B. Missing braces around the variable for case conversion

C. Using single caret instead of double caret

D. Uppercase conversion is not supported in bash

Solution

1. Step 1: Identify correct syntax for uppercase conversion

   Bash requires braces around the variable when using case conversion, like ${input^^}.

2. Step 2: Analyze the script

   The script uses $input^^ without braces, which is invalid syntax and will not convert case.

3. Final Answer:

   Missing braces around the variable for case conversion -> Option B

4. Quick Check:

   Use ${variable^^} with braces for uppercase [OK]

Hint: Always use braces ${} for case conversion in bash [OK]

Common Mistakes:

• Omitting braces around variable
• Using single caret ^ for all letters
• Assuming bash lacks uppercase conversion

5. You have a list of filenames stored in a bash array: files=("Report1.txt" "summary2.TXT" "DATA3.Txt"). You want to convert all filenames to lowercase and print them line by line. Which script correctly does this?

hard

A. for f in "${files[@]}"; do echo tolower($f); done

B. for f in "${files[@]}"; do echo ${f^^}; done

C. for f in files; do echo ${f,,}; done

D. for f in "${files[@]}"; do echo ${f,,}; done

Solution

1. Step 1: Understand the goal and array iteration

   The goal is to convert each filename to lowercase and print it. Iterating over "${files[@]}" correctly accesses each element.

2. Step 2: Check each option's correctness

   for f in "${files[@]}"; do echo ${f,,}; done uses ${f,,} to convert to lowercase and iterates correctly. for f in "${files[@]}"; do echo ${f^^}; done converts to uppercase, C iterates incorrectly (missing quotes and array expansion), D uses a non-bash function tolower().

3. Final Answer:

   for f in "${files[@]}"; do echo ${f,,}; done -> Option D

4. Quick Check:

   Lowercase array elements with ${var,,} in loop [OK]

Hint: Use for loop with ${var,,} to lowercase array items [OK]

Common Mistakes:

• Using uppercase conversion instead of lowercase
• Incorrect array iteration syntax
• Using non-existent bash functions