String comparisons (=, !=, -z, -n) in Bash Scripting - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the '=' operator do in bash string comparisons?

The '=' operator checks if two strings are exactly equal. It returns true if they match.

beginner

How do you check if two strings are NOT equal in bash?

Use the '!=' operator inside a test condition. It returns true if the strings differ.

beginner

What does '-z' check in bash string tests?

The '-z' operator checks if a string is empty (zero length). It returns true if the string has no characters.

beginner

What does '-n' check in bash string tests?

The '-n' operator checks if a string is not empty. It returns true if the string has one or more characters.

beginner

Write a simple bash if statement to check if variable 'name' is empty.

if [ -z "$name" ]; then echo "Name is empty" fi This uses '-z' to test if 'name' has zero length.

Which operator checks if two strings are equal in bash?

A -z

B !=

C =

D -n

The '=' operator tests if two strings are exactly equal.

What does the '-z' operator test for in bash?

A String is not empty

B String is empty

C Strings are equal

D Strings are not equal

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

How do you test if two strings are NOT equal in bash?

A !=

B -n

C -z

D =

The '!=' operator returns true if the strings differ.

Which operator returns true if a string is NOT empty?

A -n

B -z

C =

D !=

The '-n' operator checks if a string has one or more characters.

What will this bash test return? [ -z "hello" ]

A True

B Error

C Depends on shell

D False

Since 'hello' is not empty, '-z' returns false.

Explain how to check if a string variable is empty or not in bash using string comparison operators.

Think about testing zero length strings.

Describe the difference between '=' and '!=' operators in bash string comparisons.

One checks if strings match, the other if they differ.