Executing a command in PowerShell by setting an environment variable in cmd

Question

I want to execute a function in PowerShell from Windows CMD. Basically the requirement is to calculate the hash of a string, since Windows batch/cmd does not provide the functionality to generate a hash of a string, I've to use PowerShell.

I don't want to run a PowerShell script or put the function in a ps script as by doing so I have to bypass the Windows PowerShell security policy.

Below is the code which I am running in Hash.cmd. The code, when executed in PowerShell, runs perfectly fine.

@echo off
powershell -Command "& { Function Get-Hash([String] $String) { $StringBuilder = New-Object System.Text.StringBuilder;   [System.Security.Cryptography.HashAlgorithm]::Create("sha1").ComputeHash([System.Text.Encoding]::UTF8.GetBytes($String))|%{  [Void]$StringBuilder.Append($_.ToString("x2")); }; $StringBuilder.ToString(); }; $res=Get-Hash "Hello world"; echo $res; }"

But this is resulting in error on CMD as below:

At line:1 char:153
+ ... lder;   [System.Security.Cryptography.HashAlgorithm]::Create(sha1).Co ...
+                                                                  ~
Missing ')' in method call.
At line:1 char:153
+ ... ;   [System.Security.Cryptography.HashAlgorithm]::Create(sha1).Comput ...
+                                                              ~~~~
Unexpected token 'sha1' in expression or statement.
At line:1 char:41
+ & { Function Get-Hash([String] $String) { $StringBuilder = New-Object ...
+                                         ~
Missing closing '}' in statement block or type definition.
At line:1 char:3
+ & { Function Get-Hash([String] $String) { $StringBuilder = New-Object ...
+   ~
Missing closing '}' in statement block or type definition.
At line:1 char:157
+ ...    [System.Security.Cryptography.HashAlgorithm]::Create(sha1).Compute ...
+                                                                 ~
Unexpected token ')' in expression or statement.
At line:1 char:262
+ ... etBytes($String))|{  [Void]$StringBuilder.Append($_.ToString(x2)); }; ...
+                                                                  ~
Missing ')' in method call.
At line:1 char:262
---- TRUNCATED-----

You're having quoting issues - the whole powershell command is wrapped in double quotes, so when you use these within the powershell code it breaks. Change the double quotes "sha1" / "x2" / "Hello world" to single quotes. — henrycarteruk
– henrycarteruk, Commented Feb 6, 2019 at 11:24

henrycarteruk · Accepted Answer · 2019-02-06 12:00:54Z

4

You're having quoting issues because you're using double quotes within double quotes which breaks the quoting.

As the strings in your code that are double quoted don't require expansion (see about_quoting_rules), you can just change the double quotes "sha1" / "x2" / "Hello world" to single quotes eg 'sha1'

EDIT: Working code for me:

powershell -command "& { Function Get-Hash([String]$String) { $StringBuilder = New-Object System.Text.StringBuilder;   [System.Security.Cryptography.HashAlgorithm]::Create('sha1').ComputeHash([System.Text.Encoding]::UTF8.GetBytes($String))|%{  [Void]$StringBuilder.Append($_.ToString('X2')); }; $StringBuilder.ToString(); }; $res=Get-Hash 'Hello world'; echo $res; }"

edited Feb 6, 2019 at 12:00

answered Feb 6, 2019 at 11:28

henrycarteruk

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2 Comments

Varun Kaushik Over a year ago

Thanks! I changed the "sha1" / "x2" / "Hello world" to 'sha1' / 'x2' / 'Hello world'. Now i am getting the below error At line:1 char:223 + ... $String)) | { [Void]$StringBuilder.Append($_.ToString('x2')); }; $St ... + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Expressions are only allowed as the first element of a pipeline. + CategoryInfo : ParserError: (:) [], ParentContainsErrorRecordException + FullyQualifiedErrorId : ExpressionsMustBeFirstInPipeline

henrycarteruk Over a year ago

I don't get that error, it works for me and returns the hash - I've included my code but it only the quotes that have changed...

Varun Kaushik · Accepted Answer · 2019-02-06 12:06:22Z

0

The issue was that I was using % in place for Foreach-Object

Below is the correct cmd script

@echo off
powershell -command "& { Function Get-Hash([String] $String) { $StringBuilder =  New-Object System.Text.StringBuilder;   [System.Security.Cryptography.HashAlgorithm]::Create('sha1').ComputeHash([System.Text.Encoding]::UTF8.GetBytes($String)) | Foreach-object {  [Void]$StringBuilder.Append($_.ToString('x2')); }; $StringBuilder.ToString(); }; $hash=Get-Hash 'Hello World'; echo $hash; }"

answered Feb 6, 2019 at 12:06

Varun Kaushik

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1 Comment

mklement0 Over a year ago

% is a built-in alias for ForEach-Object, so that can't be the problem. powershell -c "1, 2 | % { $_ + 1 }" works just fine, for instance.

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