Running commands in PowerShell that require a format that will not run natively in PowerShell could be a difficult task, or can it? PowerShell provides a way to store, for example, a JSON as a string, enter here-string. A here-string is a single or double quoted string in which the quotation marks are interpreted literally. An example would be invoking a Rest API that requires a JSON body. Lets take a look at an example and see how here-strings work.

Trying to store JSON in a variable will return the following error:

`$Body = { “apple”: [ “red”, “green” ], “grape”: [ “green”, “red” ], “blueberry”: “blue” } At line:3 char:12

• "apple": [
  

•        ~
  

Unexpected token ‘:’ in expression or statement. At line:6 char:6

• ],
  

•  ~
  

Missing argument in parameter list. At line:10 char:6

• ],
  

•  ~
  

Missing argument in parameter list. + CategoryInfo : ParserError: (:) [], ParentContainsErrorRecordException + FullyQualifiedErrorId : UnexpectedToken `Oh man… What happened? PowerShell does not understand what is being done and throws an error for an unexpected token. Lets declare this as a here-string by using

@' at the start and end of the JSON variable.

$Body = @' { "apple": [ "red", "green" ], "grape": [ "green", "red" ], "blueberry": "blue" } '@ Great! No errors were thrown, but… Why?

Notice the

@' at the beginning and end, this tells PowerShell to create a here-string and store this string in a variable. Also, a rule to follow: the

@' must be on their own line at the start and end of the declaration or the here-string will not be declared.

# This will not work, PowerShell will not throw an error, but thinks you are still working to create something. $Body = @'{ "apple": [ "red", "green" ], "grape": [ "green", "red" ], "blueberry": "blue" } '@ We can also store variables in a here-string, but that requires double quotes after the

@ . The same rules apply as using single quoted here-strings.

$Red = 'red' $Green = 'green' $Blue = 'blue' $Body = @" { "apple": [ $Red, $Green ], "grape": [ $Green, $Red ], "blueberry": $Blue } "@ Now that we built our here-string, we can now invoke a Rest API and do something with it. This will help when a vendor supplies a JSON payload to be used in a Rest API, all that needs to be done is substitute your values in a here-string and invoke the Rest API. As always, practice makes perfect, try running examples in the console before running in a production environment. Here-strings will save you some lines of code and time when building your PowerShell scripts.

To learn about here-strings, visit Microsoft’s documentation on quoting rules.
https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_quoting_rules?view=powershell-6

Chris Liquori - Twitter: @pwshliquori