Comparison operators (-eq, -ne, -gt, -lt) in PowerShell

Introduction

Comparison operators help you check if values are equal, different, or if one is bigger or smaller than another. This is useful to make decisions in scripts.

Check if a user input matches a password.

Compare numbers to see if a score is higher than a target.

Find out if two strings are the same.

Decide if a file size is larger than a limit.

Run different commands based on a condition.

Syntax

PowerShell

value1 -eq value2  # equals
value1 -ne value2  # not equals
value1 -gt value2  # greater than
value1 -lt value2  # less than

Use -eq to test if two values are equal.

Use -ne to test if two values are not equal.

Examples

This checks if 5 is equal to 5. It returns $True.

PowerShell

5 -eq 5

This checks if the word "apple" is not equal to "orange". It returns $True.

PowerShell

"apple" -ne "orange"

This checks if 10 is greater than 7. It returns $True.

PowerShell

10 -gt 7

This checks if 3 is less than 2. It returns $False.

PowerShell

3 -lt 2

Sample Program

This script prints the result of four comparisons using the operators. It shows $True or $False for each.

PowerShell

Write-Output (5 -eq 5)
Write-Output (10 -ne 10)
Write-Output (7 -gt 3)
Write-Output (2 -lt 4)

Important Notes

Comparison operators return $True or $False, which are Boolean values.

Strings are compared by their text content, not by case sensitivity unless specified.

Use parentheses to make sure comparisons are evaluated correctly in complex expressions.

Summary

Comparison operators help you compare values easily in PowerShell.

Use -eq, -ne, -gt, and -lt for equals, not equals, greater than, and less than.

They return $True or $False to help your script decide what to do next.

Practice

1. Which PowerShell operator checks if two values are equal?

easy

A. -eq

B. -ne

C. -gt

D. -lt

Solution

1. Step 1: Understand the meaning of each operator

   -eq means equals, -ne means not equals, -gt means greater than, -lt means less than.

2. Step 2: Identify the operator for equality

   The operator that checks if two values are equal is -eq.

3. Final Answer:

   -eq -> Option A

4. Quick Check:

   Equals operator = -eq [OK]

Hint: Remember: eq means equal, ne means not equal [OK]

Common Mistakes:

• Confusing -eq with -ne
• Mixing -gt and -lt
• Using == instead of -eq

2. Which of the following is the correct syntax to check if variable $a is greater than 10 in PowerShell?

easy

A. if ($a -gt 10) { }

B. if ($a > 10) { }

C. if ($a -lt 10) { }

D. if ($a -eq 10) { }

Solution

1. Step 1: Recall PowerShell comparison syntax

   PowerShell uses -gt for greater than, not > like some other languages.

2. Step 2: Match the correct operator

   The correct syntax to check if $a is greater than 10 is if ($a -gt 10) { }.

3. Final Answer:

   if ($a -gt 10) { } -> Option A

4. Quick Check:

   Greater than operator = -gt [OK]

Hint: Use -gt for greater than, not > in PowerShell [OK]

Common Mistakes:

• Using > instead of -gt
• Confusing -lt with -gt
• Missing parentheses in if statement

3. What will be the output of this PowerShell code?

$x = 5
if ($x -ne 5) { 'No' } else { 'Yes' }

medium

A. 5

B. No

C. Yes

D. False

Solution

1. Step 1: Evaluate the condition $x -ne 5

   $x is 5, so $x -ne 5 means 5 not equal to 5, which is False.

2. Step 2: Determine which block runs

   Since condition is False, the else block runs, outputting 'Yes'.

3. Final Answer:

   Yes -> Option C

4. Quick Check:

   5 not equal 5 is False, so else runs [OK]

Hint: -ne means not equal; false triggers else block [OK]

Common Mistakes:

• Thinking -ne means equal
• Confusing output with variable value
• Ignoring else block

4. Identify the error in this PowerShell snippet:

$num = 10
if ($num -gt 5) { 'Greater' } elseif ($num -lt 5) { 'Smaller' } else { 'Equal' }

medium

A. Missing closing brace for if block

B. No error, code runs correctly

C. Incorrect use of elseif instead of else if

D. Using -gt instead of > operator

Solution

1. Step 1: Check syntax of if-elseif-else

   PowerShell supports elseif as one word; braces are balanced.

2. Step 2: Verify operators and structure

   -gt and -lt are correct operators; no syntax errors present.

3. Final Answer:

   No error, code runs correctly -> Option B

4. Quick Check:

   elseif is valid in PowerShell [OK]

Hint: PowerShell uses elseif as one word, not else if [OK]

Common Mistakes:

• Thinking elseif is invalid
• Expecting > instead of -gt
• Missing braces confusion

5. You want to write a PowerShell script that prints 'Valid' only if a variable $score is greater than or equal to 70. Which code snippet correctly uses comparison operators to achieve this?

hard

A. if ($score -gt 70) { 'Valid' } else { 'Invalid' }

B. if ($score -lt 70) { 'Valid' } else { 'Invalid' }

C. if ($score -eq 70) { 'Valid' } else { 'Invalid' }

D. if ($score -ge 70) { 'Valid' } else { 'Invalid' }

Solution

1. Step 1: Understand the requirement

   We want to check if $score is greater than or equal to 70.

2. Step 2: Identify the correct operator

   -ge means greater than or equal to, which matches the requirement.

3. Final Answer:

   if ($score -ge 70) { 'Valid' } else { 'Invalid' } -> Option D

4. Quick Check:

   Greater or equal operator = -ge [OK]

Hint: Use -ge for greater or equal comparisons [OK]

Common Mistakes:

• Using -gt excludes 70
• Using -eq only matches exactly 70
• Using -lt reverses logic