Powershell Script wont add $PSDefaultParameterValues to $profile-CodePudding

I'm writing a quick Powershell script to import modules and update some default parameters on various machines. I'm running into an issue where in my script when I add $PSDefaultParameterValues to the $profile it changes to System.Management.Automation.DefaultParameterDictionary which then throws an error of not being recognized as the name of a cmdlet.

Here is the code in my ps1 script

Add-Content -Path $PROFILE -Value "$PSDefaultParameterValues = @{}"

Here is what gets added to the profile

System.Management.Automation.DefaultParameterDictionary = @{}

I've tried everything from using Set-Content to using variables to avoid quotation confusion.

I appreciate the help!

CodePudding user response：

Use single quotes

Add-Content -Path $PROFILE -Value '$PSDefaultParameterValues = @{}'

These are literal strings so any variables will not expand.

CodePudding user response：

To add to tonypags' helpful answer:

Double-quoted PowerShell strings ("...") are expandable strings, i.e they perform string interpolation of embedded variable references (e.g. $PSDefaultParameterValues) and subexpressions (e.g. $(1 2))
Single-quoted strings ('...') are verbatim strings, i.e. their content is used as-is (verbatim, literally).

Thus, the automatic $PSDefaultParameterValues variable was expanded in your "..." string, which in essence means it was replaced with its .ToString() representation - which in this case is simply the type name of the variable's value.

If your entire string is meant to be used verbatim, use '...' quoting, as shown in tonypags' answer.

If you do need expansions (string interpolation), but need to selectively suppress them, escape $ characters as `$, using ` (a backtick), PowerShell's escape character, as shown in the following example:

 $enc = 'utf8'
 # Note the backtick (`) before $PSDefaultParameterValues.
 # NOTE: It is only the *outer* quoting that determines 
 #       whether expansion is performed.
 Add-Content -Path $PROFILE `
             -Value "`$PSDefaultParameterValues = @{ '*:Encoding' = '$enc' }"