Why regex enables pattern matching in Bash Scripting - Test Your Understanding

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] ]]; then echo "Match found"; fi

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

A"^hello$"

B"hello?"

C"[0-9]+"

D"hello"

Attempts:

3 left

💡 Hint

Common Mistakes

Using anchors like ^ or $ which restrict the match to start or end of the string.

Using patterns that match numbers instead of the word 'hello'.

The regex "hello" matches the exact word 'hello' anywhere in the text.

2fill in blank

medium

Complete the code to match any string that starts with 'file' followed by digits.

Bash Scripting

if [[ $filename =~ [1] ]]; then echo "Valid file name"; fi

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

A"^file[0-9]+$"

B"file.*"

C"file[0-9]+"

D"file[0-9]*"

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' which means zero or more digits, allowing 'file' alone.

Using anchors that restrict the match to the whole string.

The regex "file[0-9]+" matches 'file' followed by one or more digits anywhere in the string.

3fill in blank

hard

Fix the error in the regex to match an email address in the variable 'email'.

Bash Scripting

if [[ $email =~ [1] ]]; then echo "Valid email"; fi

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

A"[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}"

B"[a-z]+@[a-z]+\\.[a-z]+"

C"[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}"

D"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a single backslash which is not enough inside double quotes.

Not escaping the dot, causing it to match any character.

In bash regex, the dot must be escaped with double backslash \\ to match a literal dot.

4fill in blank

hard

Fill both blanks to create a regex that matches strings starting with 'log' and ending with '.txt'.

Bash Scripting

if [[ $filename =~ [1] && $filename =~ [2] ]]; then echo "Log file detected"; fi

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

A"^log"

B"log"

C"\.txt$"

D"txt$"

Attempts:

3 left

💡 Hint

Common Mistakes

Not using anchors '^' and '$' to specify start and end.

Not escaping the dot in '.txt'.

The first regex '^log' matches strings starting with 'log'. The second '\.txt$' matches strings ending with '.txt'.

5fill in blank

hard

Fill all three blanks to create a regex that matches a date in 'YYYY-MM-DD' format.

Bash Scripting

if [[ $date =~ ^[1]-[2]-[3]$ ]]; then echo "Valid date format"; fi

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

A[0-9]{4}

B(0[1-9]|1[0-2])

C(0[1-9]|[12][0-9]|3[01])

D[0-9]{2}

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect digit counts for year.

Not restricting month and day to valid ranges.

The regex matches 4 digits for year, then a month between 01-12, then a day between 01-31.