I am using Powershell to request a password from a user if not provided, based upon another answer. I then pass the password (no pun intended) to some program, do-something.exe. Rather than have an intermediate variable, I tried to convert the password to a normal string "inline":
[CmdletBinding()]
Param(
[Parameter(Mandatory, HelpMessage="password?")] [SecureString]$password
)
do-something password=${[Runtime.InteropServices.Marshal]::PtrToStringAuto([Runtime.InteropServices.Marshal]::SecureStringToBSTR($password))}
That doesn't work. I could only get it to work using a temporary, intermediate variable:
[CmdletBinding()]
Param(
[Parameter(Mandatory, HelpMessage="password?")] [SecureString]$password
)
$pwd=[Runtime.InteropServices.Marshal]::PtrToStringAuto([Runtime.InteropServices.Marshal]::SecureStringToBSTR($password))
do-something.exe password=$pwd
Did I make a mistake trying to evaluate the password inline when invoking do-something.exe? How can this be done?
${...} is a variable reference, and whatever ... is is taken verbatim as a variable name.
Enclosing a vairable name in {...} is typically not necessary, but is required in two cases: (a) if a variable name contains special characters and/or (b) in the context of an expandable string ("..."), to disambiguate the variable name from subsequent characters - see this answer
In order to embed an expression or command as part of an argument, use $(...), the subexpression operator, and preferably enclose the entire argument in "..." - that way, the entire argument is unambiguously passed as a single argument, whereas an unquoted token that starts with a $(...) subexpression would be passed as (at least) two arguments (see this answer).
If an expression or command by itself forms an argument, (...), the grouping operator is sufficient and usually preferable - see this answer
Therefore:
[CmdletBinding()]
param(
[Parameter(Mandatory, HelpMessage="password?")]
[SecureString] $password
)
# Note the use of $(...) and the enclosure of the whole argument in "..."
do-something "password=$([Runtime.InteropServices.Marshal]::PtrToStringBSTR([Runtime.InteropServices.Marshal]::SecureStringToBSTR($password)))"
Also note:
On Windows it doesn't make a difference (and on Unix [securestring] instances offer virtually no protection and should be avoided altogether), but it should be [Runtime.InteropServices.Marshal]::PtrToStringBSTR(), not [Runtime.InteropServices.Marshal]::PtrToStringAuto()
As Santiago Squarzon points out, there is an easier way to convert a SecureString instance to its plain-text equivalent (which should generally be avoided[1], however, and, more fundamentally, use of [securestring] in new projects is discouraged[2]):
[pscredential]::new('unused', $password).GetNetworkCredential().Password
[1] A plain-text representation of a password stored in a .NET string lingers in memory for an unspecified time that you cannot control. More specifically, if it is part of a process command line, as in your case, it can be discovered that way. Of course, if the CLI you're targeting offers no way to authenticate other than with a plain-text password, you have no other choice.
[2] See this answer, which links to this .NET platform-compatibility recommendation.
Related
When I study PowerShell scripting language, I try to use "Write-Output" command to display variable.
I use a different method to create variables.
Example:
$myvariable = 0x5555
Set-Variable -Name myvariable2 -Value 0x5555
The data type of these two variables is Int32.
When I use the command as below,
Write-Output $myvariable $myvariable2
the result is 21845 and 0x5555.
What's different between these two variables?
How can I display format result like printf %d %x?
PetSerAl, as many times before, has given the crucial pointer in a comment (and later helped improve this answer):
Written as of PowerShell Core 6.2.0.
PowerShell parses an unquoted literal argument that looks like a number as a number and wraps it in a "half-transparent" [psobject] instance, whose purpose is to also preserve the exact argument as specified as a string.
By half-transparent I mean that the resulting $myVariable2:
primarily is a number - a regular (unwrapped) [int] instance - for the purpose of calculations; e.g., $myVariable2 + 1 correctly returns 21846
additionally, it shows that it is a number when you ask for its type with .GetType() or via the Get-Member cmdlet; in other words: in this case PowerShell pretends that the wrapper isn't there (see below for a workaround).
situationally behaves like a string - returning the original argument literal exactly as specified - in the context of:
output formatting, both when printing directly to the console and generally with Out-* cmdlets such as Out-File (but not Set-Content) and Format-* cmdlets.
string formatting with -f, PowerShell's format operator (which is based on .NET's String.Format() method; e.g., 'The answer is {0}' -f 42 is equivalent to [string]::Format('The answer is {0}', 42)).
Surprisingly, it does not behave like a string inside an expandable string ("$myVariable2") and when you call the .ToString() method ($myVariable2.ToString()) and (therefore also) with Set-Content.
However, the original string representation can be retrieved with $myVariable2.psobject.ToString()
Note that specifying number literals as command arguments is inherently ambiguous, because even string arguments generally don't need quoting (unless they contain special characters), so that, for instance, an argument such as 1.0 could be interpreted as a version string or as a floating-point number.
PowerShell's approach to resolving the ambiguity is to parse such a token as a number, which, however, situationally acts as a string[1], as shown above.
The ambiguity can be avoided altogether by typing parameters so as to indicate whether an argument bound to it is a string or a number.
However, the -Value parameter of the Set-Variable and New-Variable cmdlets is - of necessity - [object] typed, because it must be able to accept values of any type, and these cmdlets don't have a parameter that would let you indicate the intended data type.
The solution is to force the -Value argument to be treated as the result of an expression rather than as an unquoted literal argument, by enclosing it in (...):
# Due to enclosing in (...), the value that is stored in $myvariable2
# is *not* wrapped in [psobject] and therefore behaves the same as
# $myvariable = 0x55555
Set-Variable -Name myvariable2 -Value (0x5555)
Conversely, if you don't apply the above solution, you have two choices for unwrapping $myvariable2's value on demand:
# OK: $myvariable isn't wrapped in [psobject], so formatting it as a
# hex. number works as expected:
PS> 'hex: 0x{0:x}' -f $myvariable
hex: 0x5555 # OK: Literal '0x' followed by hex. representation of the [int]
# !! Does NOT work as expected, because $myvariable2 is treated as a *string*
# !! That is, {0:x} is effectively treated as just {0}, and the string
# !! representation stored in the [psobject] wrapper is used as-is.
PS> 'hex: 0x{0:x}' -f $myvariable2
hex: 0x0x5555 # !! Note the extra '0x'
# Workaround 1: Use a *cast* (with the same type) to force creation of
# a new, *unwrapped* [int] instance:
PS> 'hex: 0x{0:x}' -f [int] $myvariable2
hex: 0x5555 # OK
# Workaround 2: Access the *wrapped* object via .psobject.BaseObject.
# The result is an [int] that behaves as expected.
PS> 'hex: 0x{0:x}' -f $myvariable2.psobject.BaseObject
hex: 0x5555 # OK
Note: That -f, the format operator, unexpectedly treats a [psobject]-wrapped number as a string is the subject of GitHub issue #17199; sadly, the behavior was declared to be by design.
Detecting a [psobject]-wrapped value:
The simplest solution is to use -is [psobject]:
PS> $myvariable -is [psobject]
False # NO wrapper object
PS> $myvariable2 -is [psobject]
True # !! wrapper object
(PetSerAl offers the following, less obvious alternative: [Type]::GetTypeArray((, $myvariable2)), which bypasses PowerShell's hiding-of-the-wrapper trickery.)
[1] Preserving the input string representation in implicitly typed numbers passed as command arguments:
Unlike traditional shells, PowerShell uses rich types, so that an argument literal such as 01.2 is instantly parsed as a number - a [double] in this case, and if it were used as-is, it would result in a different representation on output, because - once parsed as a number - default output formatting is applied on output (where the number must again be turned into a string):
PS> 01.2
1.2 # !! representation differs (and is culture-sensitive)
However, the intent of the target command may ultimately be to treat the argument as a string and in that case you do not want the output representation to change.
(Note that while you can disambiguate numbers from strings by using quoting (01.2 vs. '01.2'), this is not generally required in command arguments, the same way it isn't required in traditional shells.)
It is for that reason that a [psobject] wrapper is used to capture the original string representation and use it on output.
Note: Arguably, a more consistent approach would have been to always treat unquoted literal arguments as strings, except when bound to explicitly numerically typed parameters in PowerShell commands.
This is a necessity for invoking external programs, to which arguments can only ever be passed as strings.
That is, after initial parsing as a number, PowerShell must use the original string representation when building the command line (Windows) / passing the argument (Unix-like platforms) as part of the invocation of the external program.
If it didn't do that, arguments could inadvertently be changed, as shown above (in the example above, the external program would receive string 1.2 instead of the originally passed 01.2).
You can also demonstrate the behavior using PowerShell code, with an untyped parameter - though note that is generally preferable to explicitly type your parameters:
PS> & { param($foo) $foo.GetType().Name; $foo } -foo 01.2
Double # parsed as number - a [double]
01.2 # !! original string representation, because $foo wasn't typed
$foo is an untyped parameter, which means that the type that PowerShell inferred during initial parsing of literal 01.2 is used.
Yet, given that the command (a script block ({ ... }) in this case) didn't declare a parameter type for $foo, the [psobject] wrapper that is implicitly used shows the original string representation on output.
The first question is already answered by #PetSerAl in the comments. Your second question:
How can I display format result like printf %d %x
Use PowerShell string formatting to obtain the desired results.
Trying to get get param(...) to be have some basic error checking... one thing that puzzles me is how to detect invalid switch and flags that are not in the param list?
function abc {
param(
[switch]$one,
[switch]$two
)
}
When I use it:
PS> abc -One -Two
# ok... i like this
PS> abc -One -Two -NotAValidSwitch
# No Error here for -NotAValidSwitch? How to make it have an error for invalid switches?
As Santiago Squarzon, Abraham Zinala, and zett42 point out in comments, all you need to do is make your function (or script) an advanced (cmdlet-like) one:
explicitly, by decorating the param(...) block with a [CmdletBinding()] attribute.
and/or implicitly, by decorating at least one parameter variable with a [Parameter()] attribute.
function abc {
[CmdletBinding()] # Make function an advanced one.
param(
[switch]$one,
[switch]$two
)
}
An advanced function automatically ensures that only arguments that bind to explicitly declared parameters may be passed.
If unexpected arguments are passed, the invocation fails with a statement-terminating error.
Switching to an advanced script / function has side effects, but mostly beneficial ones:
You gain automatic support for common parameters, such as -OutVariable or -Verbose.
You lose the ability to receive unbound arguments, via the automatic $args variable variable (which is desired here); however, you can declare a catch-all parameter for any remaining positional arguments via [Parameter(ValueFromRemainingArguments)]
To accept pipeline input in an advanced function or script, a parameter must explicitly be declared as pipeline-binding, via [Parameter(ValueFromPipeline)] (objects as a whole) or [Parameter(ValueFromPipelineByPropertyName)] (value of the property of input objects that matches the parameter name) attributes.
For a juxtaposition of simple (non-advanced) and advanced functions, as well as binary cmdlets, see this answer.
If you do not want to make your function an advanced one:
Check if the automatic $args variable - reflecting any unbound arguments (a simpler alternative to $MyInvocation.UnboundArguments) - is empty (an empty array) and, if not, throw an error:
function abc {
param(
[switch]$one,
[switch]$two
)
if ($args.Count) { throw "Unexpected arguments passed: $args" }
}
Potential reasons for keeping a function a simple (non-advanced) one:
To "cut down on ceremony" in the parameter declarations, e.g. for pipeline-input processing via the automatic $input variable alone.
Generally, for simple helper functions, such as for module- or script-internal use that don't need support for common parameters.
When a function acts as a wrapper for an external program to which arguments are to be passed through and whose parameters (options) conflict with the names and aliases of PowerShell's common parameters, such as -verbose or -ov (-Out-Variable).
What isn't a good reason:
When your function is exported from a module and has an irregular name (not adhering to PowerShell's <Verb>-<Noun> naming convention based on approved verbs) and you want to avoid the warning that is emitted when you import that module.
First and foremost, this isn't an issue of simple vs. advanced functions, but relates solely to exporting a function from a module; that is, even an irregularly named simple function will trigger the warning. And the warning exists for a good reason: Functions exported from modules are typically "public", i.e. (also) for use by other users, who justifiable expect command names to follow PowerShell's naming conventions, which greatly facilitates command discovery. Similarly, users will expect cmdlet-like behavior from functions exported by a module, so it's best to only export advanced functions.
If you still want to use an irregular name while avoiding a warning, you have two options:
Disregard the naming conventions altogether (not advisable) and choose a name that contains no - character, e.g. doStuff - PowerShell will then not warn. A better option is to choose a regular name and define the irregular names as an alias for it (see below), but note that even aliases have a (less strictly adhered-to) naming convention, based on an official one or two-letter prefix defined for each approved verb, such as g for Get- and sa for Start- (see the approved-verbs doc link above).
If you do want to use the <Verb>-<Noun> convention but use an unapproved verb (token before -), define the function with a regular name (using an approved verb) and also define and export an alias for it that uses the irregular name (aliases aren't subject to the warning). E.g., if you want a command named Ensure-Foo, name the function Set-Foo, for instance, and define Set-Alias Ensure-Foo Set-Foo. Do note that both commands need to be exported and are therefore visible to the importer.
Finally, note that the warning can also be suppressed on import, namely via Import-Module -DisableNameChecking. The downside of this approach - aside from placing the burden of silencing the warning on the importer - is that custom classes exported by a module can't be imported this way, because importing such classes requires a using module statement, which has no silencing option (as of PowerShell 7.2.1; see GitHub issue #2449 for background information.
I downloaded the npm package for merge junit reports - https://www.npmjs.com/package/junit-merge.
The problem is that I have multiple files to merge and I am trying to use string variable to hold file names to merge.
When I write the script myslef like:
junit-merge a.xml b.xml c.xml
This works, the merged file is being created, but when I do it like
$command = "a.xml b.xml c.xml"
junit-merge $command
This does not work. The error is
Error: File not found
Has anyone faced similar issues?
# WRONG
$command = "a.xml b.xml c.xml"; junit-merge $command
results in command line junit-merge "a.xml b.xml c.xml"[1], i.e. it passes a string with verbatim value a.xml b.xml c.xml as a single argument to junit-merge, which is not the intent.
PowerShell does not act like POSIX-like shells such as bash do in this regard: In bash, the value of variable $command - due to being referenced unquoted - would be subject to word splitting (one of the so-called shell expansions) and would indeed result in 3 distinct arguments (though even there an array-based invocation would be preferable).
PowerShell supports no bash-like shell expansions[2]; it has different, generally more flexible constructs, such as the splatting technique discussed below.
Instead, define your arguments as individual elements of an array, as justnotme advises:
# Define the *array* of *individual* arguments.
$command = "a.xml", "b.xml", "c.xml"
# Pass the array to junit-merge, which causes PowerShell
# to pass its elements as *individual arguments*; it is the equivalent of:
# junit-merge a.xml b.xml c.xml
junit-merge $command
This is an application of a PowerShell technique called splatting, where you specify arguments to pass to a command via a variable:
Either (typically only used for external programs, as in your case):
As an array of arguments to pass individually as positional arguments, as shown above.
Or (more typically when calling PowerShell commands):
As a hashtable to pass named parameter values, in which you must replace the $ sigil in the variable reference with #; e.g., in your case #command; e.g., the following is the equivalent of calling Get-ChildItem C:\ -Directory:
$paramVals = #{ LiteralPath = 'C:\'; Directory = $true }; Get-ChildItem #paramVals
Caveat re array-based splatting:
Due to a bug detailed in GitHub issue #6280, PowerShell doesn't pass empty arguments through to external programs (applies to all Windows PowerShell versions / and as of PowerShell (Core) 7.2.x; a fix may be coming in 7.3, via the $PSNativeCommandArgumentPassing preference variable, which in 7.2.x relies on an explicitly activated experimental feature).
E.g., foo.exe "" unexpectedly results in just foo.exe being called.
This problem equally affects array-based splatting, so that
$cmdArgs = "", "other"; foo.exe $cmdArgs results in foo.exe other rather than the expected foo.exe "" other.
Optional use of # with array-based splatting:
You can use the # sigil also with arrays, so this would work too:
junit-merge #command
There is a subtle distinction, however.
While it will rarely matter in practice,
the safer choice is to use $, because it guards against (the however hypothetical) accidental misinterpretation of a --% array element you intend to be a literal.
Only the # syntax recognizes an array element --% as the special stop-parsing symbol, --%
Said symbol tells PowerShell not to parse the remaining arguments as it normally would and instead pass them through as-is - unexpanded, except for expanding cmd.exe-style variable references such as %USERNAME%.
This is normally only useful when not using splatting, typically in the context of being able to use command lines that were written for cmd.exe from PowerShell as-is, without having to account for PowerShell's syntactical differences.
In the context of splatting, however, the behavior resulting from --% is non-obvious and best avoided:
As in direct argument passing, the --% is removed from the resulting command line.
Argument boundaries are lost, so that a single array element foo bar, which normally gets placed as "foo bar" on the command line, is placed as foo bar, i.e. effectively as 2 arguments.
[1] Your call implies the intent to pass the value of variable $command as a single argument, so when PowerShell builds the command line behind the scenes, it double-quotes the verbatim a.xml b.xml c.xml string contained in $command to ensure that. Note that these double quotes are unrelated to how you originally assigned a value to $command.
Unfortunately, this automatic quoting is broken for values with embedded " chars. - see this answer, for instance.
[2] As a nod to POSIX-like shells, PowerShell does perform one kind of shell expansion, but (a) only on Unix-like platforms (macOS, Linux) and (b) only when calling external programs: Unquoted wildcard patterns such as *.txt are indeed expanded to their matching filenames when you call an external program (e.g., /bin/echo *.txt), which is feature that PowerShell calls native globbing.
I had a similar problem. This technique from powershell worked for me:
Invoke-Expression "junit-merge $command"
I also tried the following (from a powershell script) and it works:
cmd / c "junit-merge $command"
When I study PowerShell scripting language, I try to use "Write-Output" command to display variable.
I use a different method to create variables.
Example:
$myvariable = 0x5555
Set-Variable -Name myvariable2 -Value 0x5555
The data type of these two variables is Int32.
When I use the command as below,
Write-Output $myvariable $myvariable2
the result is 21845 and 0x5555.
What's different between these two variables?
How can I display format result like printf %d %x?
PetSerAl, as many times before, has given the crucial pointer in a comment (and later helped improve this answer):
Written as of PowerShell Core 6.2.0.
PowerShell parses an unquoted literal argument that looks like a number as a number and wraps it in a "half-transparent" [psobject] instance, whose purpose is to also preserve the exact argument as specified as a string.
By half-transparent I mean that the resulting $myVariable2:
primarily is a number - a regular (unwrapped) [int] instance - for the purpose of calculations; e.g., $myVariable2 + 1 correctly returns 21846
additionally, it shows that it is a number when you ask for its type with .GetType() or via the Get-Member cmdlet; in other words: in this case PowerShell pretends that the wrapper isn't there (see below for a workaround).
situationally behaves like a string - returning the original argument literal exactly as specified - in the context of:
output formatting, both when printing directly to the console and generally with Out-* cmdlets such as Out-File (but not Set-Content) and Format-* cmdlets.
string formatting with -f, PowerShell's format operator (which is based on .NET's String.Format() method; e.g., 'The answer is {0}' -f 42 is equivalent to [string]::Format('The answer is {0}', 42)).
Surprisingly, it does not behave like a string inside an expandable string ("$myVariable2") and when you call the .ToString() method ($myVariable2.ToString()) and (therefore also) with Set-Content.
However, the original string representation can be retrieved with $myVariable2.psobject.ToString()
Note that specifying number literals as command arguments is inherently ambiguous, because even string arguments generally don't need quoting (unless they contain special characters), so that, for instance, an argument such as 1.0 could be interpreted as a version string or as a floating-point number.
PowerShell's approach to resolving the ambiguity is to parse such a token as a number, which, however, situationally acts as a string[1], as shown above.
The ambiguity can be avoided altogether by typing parameters so as to indicate whether an argument bound to it is a string or a number.
However, the -Value parameter of the Set-Variable and New-Variable cmdlets is - of necessity - [object] typed, because it must be able to accept values of any type, and these cmdlets don't have a parameter that would let you indicate the intended data type.
The solution is to force the -Value argument to be treated as the result of an expression rather than as an unquoted literal argument, by enclosing it in (...):
# Due to enclosing in (...), the value that is stored in $myvariable2
# is *not* wrapped in [psobject] and therefore behaves the same as
# $myvariable = 0x55555
Set-Variable -Name myvariable2 -Value (0x5555)
Conversely, if you don't apply the above solution, you have two choices for unwrapping $myvariable2's value on demand:
# OK: $myvariable isn't wrapped in [psobject], so formatting it as a
# hex. number works as expected:
PS> 'hex: 0x{0:x}' -f $myvariable
hex: 0x5555 # OK: Literal '0x' followed by hex. representation of the [int]
# !! Does NOT work as expected, because $myvariable2 is treated as a *string*
# !! That is, {0:x} is effectively treated as just {0}, and the string
# !! representation stored in the [psobject] wrapper is used as-is.
PS> 'hex: 0x{0:x}' -f $myvariable2
hex: 0x0x5555 # !! Note the extra '0x'
# Workaround 1: Use a *cast* (with the same type) to force creation of
# a new, *unwrapped* [int] instance:
PS> 'hex: 0x{0:x}' -f [int] $myvariable2
hex: 0x5555 # OK
# Workaround 2: Access the *wrapped* object via .psobject.BaseObject.
# The result is an [int] that behaves as expected.
PS> 'hex: 0x{0:x}' -f $myvariable2.psobject.BaseObject
hex: 0x5555 # OK
Note: That -f, the format operator, unexpectedly treats a [psobject]-wrapped number as a string is the subject of GitHub issue #17199; sadly, the behavior was declared to be by design.
Detecting a [psobject]-wrapped value:
The simplest solution is to use -is [psobject]:
PS> $myvariable -is [psobject]
False # NO wrapper object
PS> $myvariable2 -is [psobject]
True # !! wrapper object
(PetSerAl offers the following, less obvious alternative: [Type]::GetTypeArray((, $myvariable2)), which bypasses PowerShell's hiding-of-the-wrapper trickery.)
[1] Preserving the input string representation in implicitly typed numbers passed as command arguments:
Unlike traditional shells, PowerShell uses rich types, so that an argument literal such as 01.2 is instantly parsed as a number - a [double] in this case, and if it were used as-is, it would result in a different representation on output, because - once parsed as a number - default output formatting is applied on output (where the number must again be turned into a string):
PS> 01.2
1.2 # !! representation differs (and is culture-sensitive)
However, the intent of the target command may ultimately be to treat the argument as a string and in that case you do not want the output representation to change.
(Note that while you can disambiguate numbers from strings by using quoting (01.2 vs. '01.2'), this is not generally required in command arguments, the same way it isn't required in traditional shells.)
It is for that reason that a [psobject] wrapper is used to capture the original string representation and use it on output.
Note: Arguably, a more consistent approach would have been to always treat unquoted literal arguments as strings, except when bound to explicitly numerically typed parameters in PowerShell commands.
This is a necessity for invoking external programs, to which arguments can only ever be passed as strings.
That is, after initial parsing as a number, PowerShell must use the original string representation when building the command line (Windows) / passing the argument (Unix-like platforms) as part of the invocation of the external program.
If it didn't do that, arguments could inadvertently be changed, as shown above (in the example above, the external program would receive string 1.2 instead of the originally passed 01.2).
You can also demonstrate the behavior using PowerShell code, with an untyped parameter - though note that is generally preferable to explicitly type your parameters:
PS> & { param($foo) $foo.GetType().Name; $foo } -foo 01.2
Double # parsed as number - a [double]
01.2 # !! original string representation, because $foo wasn't typed
$foo is an untyped parameter, which means that the type that PowerShell inferred during initial parsing of literal 01.2 is used.
Yet, given that the command (a script block ({ ... }) in this case) didn't declare a parameter type for $foo, the [psobject] wrapper that is implicitly used shows the original string representation on output.
The first question is already answered by #PetSerAl in the comments. Your second question:
How can I display format result like printf %d %x
Use PowerShell string formatting to obtain the desired results.
I have a script with mandatory parameters which we use to install some SQL components including user name and passwords like below:
param(
[Parameter(Mandatory=$True,HelpMessage="SQL Server password")]
[ValidateNotNullOrEmpty()]
[string] $SqlServerPassword
)
So when a user runs this script, he/she will need to include the -SqlServerPassword 'SpecialCharacters' variable string. I know best practice is to place the string inside a single quote, but its been a hard path training some of our installation managers and it messes up because our password vault includes special characters which without single quotes causes issues.
How can I re-write the above to ensure that even if the user passes the password without it being in single quotes, that it will be in single quotes? Thanks!
What you're asking for cannot be done, if the string is to be passed as an argument, because that would require deactivating the command-line parser - the very mechanism that recognizes individual arguments, evaluates variable references and subexpressions contained in them, and binds them to parameters.
With a limited set of special characters you could ignore the value bound by the parser and manually parse $MyInvocation.Line, the raw command line, but not only is that ill-advised, it would break with characters such as | and ;
However, you can achieve what you want via an interactive prompt.
While you also get such a prompt with your code if the user happens not to pass a -SqlServerPassword argument on the command line, it doesn't prevent potentially incorrect command-line use.
(Also, this automatic prompting is not user-friendly and has quirks, such as not being able to start a value with !).
If feasible, you could require users to enter the value interactively (and not also allow passing a value as an argument) using Read-Host, in which case quoting need not - and must not - be used:
param(
# Do NOT define $SqlServerPassword as a parameter (but define others)
)
# Prompt the user for the password.
# The input is invariably treated as a literal.
Write-Host "Please enter the SQL Server password:"
[string] $SqlServerPassword = Read-Host
# Validate the user's input.
if (-not $SqlServerPassword) { Throw 'Aborted.' }
# ...
Note: Read-Host has a -Prompt parameter, which accepts a prompt string directly, but if you were to use it, you wouldn't be able to enter values that start with !; therefore, the prompt was written with a separate Write-Host statement above.