Exchange shell: Using double quotes or single quotes in commands or scripts

Another frequently asked question about PowerShell/Exchange shell, and one that I myself had during the initial foray with the shell - what's the difference between using double quotes and single quotes in a shell command or script?

The biggest difference, and the only one I'm aware of, is the fact that using double quotes - e.g. "$mailboxes", expands the variable. (Note, if the variable has not been used/defined or doesn't have any value, you get no output.)

When using single quotes - e.g. '$mailboxes', it is treated as a string.

To see the difference in action:

$mailboxes = Get-Mailbox

Now that we have captured the value(s) of mailbox(es) in a variable (actually an array... it can have a single or multiple values. In this case, a single mailbox, if you only have one, or multiple mailboxes).

Next, let's get some output from this. First, let's try with single quotes:

Write-Host 'This is a list of all my mailboxes: $mailboxes'

What you get is simply:

This is a list of all my mailboxes: $mailboxes

Now let's try with double quotes:

Write-Host "This is a list of all my mailboxes: $mailboxes"

The output will list all your mailboxes, as seen below:

This is a list of all my mailboxes: Jane Doe John Doe....

I haven't found any side-effects of using double-quotes, except when you really want a particular variable/string to be treated as a string.