Powershell Script wont add $PSDefaultParameterValues to $profile

user_19446817 0
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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!

default-parameters string-literals string-interpolation profile powershell
2 Answers

Use single quotes

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

These are literal strings so any variables will not expand.

user_133253670

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' }"
user_453750
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