String comparisons (=, !=, -z, -n) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the variable name is equal to "Alice".

Bash Scripting

if [ "$name" [1] "Alice" ]; then
  echo "Hello, Alice!"
fi

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

A=

B-n

C-z

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '=' when checking for equality.

Using '-z' or '-n' which check string length, not equality.

The operator '=' checks if two strings are equal in bash test expressions.

2fill in blank

medium

Complete the code to check if the variable input is not empty.

Bash Scripting

if [ [1] "$input" ]; then
  echo "Input received."
fi

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

A!=

B-z

C-n

D=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-z' which checks if the string is empty.

Using '=' or '!=' which compare strings but don't check emptiness.

The '-n' operator returns true if the string length is not zero (not empty).

3fill in blank

hard

Fix the error in the code to check if var is empty.

Bash Scripting

if [ [1] "$var" ]; then
  echo "Variable is empty."
fi

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

A!=

B=

C-n

D-z

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' or '!=' without a second string to compare.

Using '-n' which checks for non-empty strings.

The '-z' operator returns true if the string length is zero (empty).

4fill in blank

hard

Fill both blanks to check if user is not "admin" and is not empty.

Bash Scripting

if [ "$user" [1] "admin" ] && [ [2] "$user" ]; then
  echo "Access denied."
fi

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

A!=

B-z

C-n

D=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' instead of '!=' for inequality.

Using '-z' instead of '-n' to check non-empty string.

Use '!=' to check user is not 'admin' and '-n' to check user is not empty.

5fill in blank

hard

Fill all three blanks to create a condition that checks if file is empty or equals "default.txt".

Bash Scripting

if [ [1] "$file" ] || [ "$file" [2] [3] ]; then
  echo "Using default file."
fi

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

A-z

B=

C"default.txt"

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '=' for equality check.

Not quoting the string "default.txt".

Use '-z' to check if file is empty, '=' to check equality, and '"default.txt"' as the string to compare.