Character classes ([a-z], [0-9]) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to match all lowercase letters in the string.

Bash Scripting

echo "abc123" | grep -o '[[1]]'

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

AA-Z

Ba-z

C0-9

DA-Za-z

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase letters range [A-Z] instead of lowercase.

Using digits range [0-9] which matches numbers, not letters.

The character class [a-z] matches all lowercase letters from a to z.

2fill in blank

medium

Complete the code to match all digits in the string.

Bash Scripting

echo "abc123" | grep -o '[[1]]'

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

A0-9

Ba-z

CA-Z

Da-zA-Z

Attempts:

3 left

💡 Hint

Common Mistakes

Using letter ranges like [a-z] instead of digits.

Using uppercase letter ranges [A-Z] which do not match digits.

The character class [0-9] matches all digits from 0 to 9.

3fill in blank

hard

Fix the error in the code to match lowercase letters only.

Bash Scripting

echo "Hello123" | grep -o '[[1]]'

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

AA-Z

BA-Za-z

Ca-z

D0-9

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase letters range [A-Z] which matches uppercase letters.

Using combined ranges like [A-Za-z] which matches both cases.

To match lowercase letters only, use the range [a-z].

4fill in blank

hard

Fill both blanks to match lowercase letters and digits separately.

Bash Scripting

echo "a1b2c3" | grep -o '[[1]]' | sort | uniq && echo "a1b2c3" | grep -o '[[2]]' | sort | uniq

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

Aa-z

B0-9

CA-Z

Da-zA-Z

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing uppercase letters in the ranges.

Using the same range for both blanks.

Use [a-z] to match lowercase letters and [0-9] to match digits.

5fill in blank

hard

Fill all three blanks to create a grep pattern matching lowercase letters, digits, and uppercase letters.

Bash Scripting

echo "aA1bB2cC3" | grep -o '[[1][2][3]]'

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

Aa-z

B0-9

CA-Z

D_

Attempts:

3 left

💡 Hint

Common Mistakes

Using underscores or other characters that do not match letters or digits.

Separating ranges into multiple character classes instead of combining.

Combine ranges [a-z], [0-9], and [A-Z] inside one character class to match all lowercase letters, digits, and uppercase letters.