Using Variables in PS

Question 1

All variables start with…

Answer 1

$

Question 2

Running $varName does what?

Answer 2

Echos the contents to the console.

Question 3

How can we explicitly write to the host?

Answer 3

Write-Host $var

Question 4

All variables in PS are…

Answer 4

objects

Question 5

How can I display the type of the variable?

Answer 5

$myVar.GetType()

Question 6

How can I display the properties and methods of a variable?

Answer 6

Pipe the variable to Get-Member cmdlet
eg:

$var | Get-Member

Question 7

So how could I find all the properties and methods from an object returned by Get-ChildItem?

Answer 7

Get-ChildItem | Get-Member

This actually returns a separate list for each member type that is returned. So if you set path to env: the above command will return different values than if it’s looking at a file system drive.

Question 8

How do you explicitly type a variable

Answer 8

Wrap it in square brackets e.g:

[System.Int32]$myInt = 42

Question 9

What are the shortcuts for the .NET datatypes

Answer 9

[int]
[string]
[float]
[short]
[decimal]
[single]

Question 10

When should we strongly type variables

Answer 10

When it is required by something that we’re working with. Most of the time we just use the dynamic typing

Question 11

For non-string datatypes, how do we use methods on literal values?

Answer 11

Wrap it in parentheses:

e.g. (33).GetType()

Question 12

What does wrapping in parentheses on a literal values actually do?

Answer 12

Forces PowerShell to convert it to an object.

Question 13

How do you specify:
>
=

Answer 13

• gt
• lt
• eq
• ne
• le
• ge

Question 14

For collections, what operators are available?

Answer 14

• in
• notin
• Like
• NotLike
• Match (matches on regex)

Question 15

How is implicit type coercion performed in PS?

Answer 15

Whatever value is on the right is converted to the data type on the left. So
42 -eq “042” == $True ..but
“042” -eq 42 == $False

Question 16

How are true, false and null represented in PS?

Answer 16

$true
$false
$NULL

Question 17

What is the built in variable for getting the current directory?

Answer 17

$pwd

Print Working Directory

Question 18

What is the built in variable for getting the user’s home directory

Answer 18

$Home

Question 19

How can we view info about a users scripting environment?

Answer 19

$Host

Question 20

How can we view the current process id?

Answer 20

$PID

Question 21

How do we get the current version of powershell?

Answer 21

$PSVersionTable

Question 22

How is the “current item” represented in PS?

Answer 22

$_

Question 23

How do you explcitly create a new variable in PS?

Answer 23

New-Variable -Name varName -Value varValue

Note that you don’t use the $ at the beginning of the variable name

Question 24

Once a variable is created can you create it again with New-Variable?

Answer 24

No, you have to use Set-Variable instead
E.g.
Set-Variable -Name varName -Value varValue

Question 25

How do you explicitly get the value of a variable?

Answer 25

Get-Variable varName -valueonly

Again, no $ at the beginning of the variable name.

Question 26

Calling Get-Variable varName without the -valueonly switch returns?

Answer 26

A table with the variable name and the value.

Question 27

How do you get all variables?

Answer 27

Get-Variable

Question 28

How can we clear the value of a variable?

Answer 28

Clear-Variable -Name varName

Question 29

How do we totally get rid of a variable?

Answer 29

Remove-Variable -Name varName