Quantifiers (*, +, ?) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to match zero or more 'a' characters in the string.

Bash Scripting

echo 'aaaab' | grep -E 'a[1]b'

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

A+

B*

C?

D{2}

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' which requires at least one 'a'.

Using '?' which matches zero or one 'a' only.

The '*' quantifier matches zero or more occurrences of the preceding character.

2fill in blank

medium

Complete the code to match one or more digits in the input.

Bash Scripting

echo '12345' | grep -E '[0-9][1]'

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

A+

B*

C?

D{0,}

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' which allows zero digits, so it matches empty strings.

Using '?' which matches zero or one digit only.

The '+' quantifier matches one or more occurrences of the preceding pattern.

3fill in blank

hard

Complete the code to match zero or one 'a' followed by 'b'.

Bash Scripting

echo 'ab' | grep -E 'a[1]b'

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

A?

B*

C+

D{1,2}

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' which requires at least one 'a'.

Using '*' which allows any number including many 'a's.

The '?' quantifier matches zero or one occurrence of the preceding character.

4fill in blank

hard

Fill both blanks to match a string starting with one or more 'x' followed by zero or one 'y'.

Bash Scripting

echo 'xxxy' | grep -E '^x[1]y[2]$'

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

A+

B*

C?

D{2}

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' for 'x' which allows zero 'x's, but we want at least one.

Using '+' for 'y' which requires at least one 'y'.

Use '+' to match one or more 'x' and '?' to match zero or one 'y'.

5fill in blank

hard

Fill all three blanks to match a string with zero or more 'a's, followed by one or more 'b's, then zero or one 'c'.

Bash Scripting

echo 'aaabbc' | grep -E '^a[1]b[2]c[3]$'

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

A*

B+

C?

D{3}

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' for 'a' which requires at least one 'a'.

Using '*' for 'b' which allows zero 'b's but we need at least one.

Using '+' for 'c' which requires at least one 'c'.

Use '*' for zero or more 'a's, '+' for one or more 'b's, and '?' for zero or one 'c'.