Regex in [[ ]] with =~ in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the variable 'text' contains the word 'hello' using regex.

Bash Scripting

if [[ $text [1] "hello" ]]; then
  echo "Match found"
fi

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

A=

B==

C=~

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '=~' for regex matching.

Using single brackets [ ] which do not support '=~'.

The operator '=~' is used inside [[ ]] to test if a string matches a regex pattern.

2fill in blank

medium

Complete the code to check if the variable 'input' starts with a digit using regex.

Bash Scripting

if [[ $input [1] ^[0-9] ]]; then
  echo "Starts with a digit"
fi

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

A!=

B==

C=

D=~

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '=~' for regex.

Not escaping special characters when needed.

The '=~' operator is used to match regex patterns inside [[ ]]. '^' means start of string.

3fill in blank

hard

Fix the error in the code to correctly check if 'var' contains only letters.

Bash Scripting

if [[ $var [1] ^[a-zA-Z]+$ ]]; then
  echo "Only letters"
fi

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

A=~

B==

C=

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '=~' causes the regex to be treated as a string.

Forgetting to quote the variable can cause errors if it is empty.

Use '=~' to match regex. '^[a-zA-Z]+$' matches strings with only letters.

4fill in blank

hard

Fill both blanks to check if 'filename' ends with '.txt' using regex.

Bash Scripting

if [[ $filename [1] \.[2]$ ]]; then
  echo "Text file"
fi

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

A=~

Btxt

Ctxt$

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '=~' for regex.

Not escaping the dot before 'txt'.

Use '=~' for regex matching. '\.txt$' matches strings ending with '.txt'.

5fill in blank

hard

Fill all three blanks to create a regex that matches a string with exactly 3 digits.

Bash Scripting

if [[ $code [1] ^[2][3]$ ]]; then
  echo "Three digits"
fi

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

A=~

B[0-9]

C{3}

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '=~'.

Forgetting to use curly braces for exact count.

Use '=~' for regex matching. '^[0-9]{3}$' matches exactly three digits.