Goal: I want to be able to get the MD5 of file and store it. Then use it to
verify a file on a remote server is exactly the same.

Ok... I got the MD5 from file (kinda simple really.)

The problem is that this returns a Byte[]. Compare-Object doesn't like this
for some reason and for seemingly obvious reasons .ToString() doesn't
convert it correctly.

Any Ideas?

"Brandon Shell" <tshell.mask@gmail.com> wrote in message
news:%23ciNSGhGHHA.1804@TK2MSFTNGP02.phx.gbl...
> Goal: I want to be able to get the MD5 of file and store it. Then use it
> to verify a file on a remote server is exactly the same.

Ok... ignore me... I'm apparently prematurely asking for help. I figured it
out.

I didn't realize that compare-objects doesn't return anything if the objects
are the same... silly me.. I was expecting a $true or $false.

"Brandon Shell" <tshell.mask@gmail.com> wrote in message
news:O8szF3hGHHA.3468@TK2MSFTNGP04.phx.gbl...
> Ok... I got the MD5 from file (kinda simple really.)
>
> The problem is that this returns a Byte[]. Compare-Object doesn't like
> this for some reason and for seemingly obvious reasons .ToString() doesn't
> convert it correctly.
>
> Any Ideas?
>
> "Brandon Shell" <tshell.mask@gmail.com> wrote in message
> news:%23ciNSGhGHHA.1804@TK2MSFTNGP02.phx.gbl...
>> Goal: I want to be able to get the MD5 of file and store it. Then use it
>> to verify a file on a remote server is exactly the same.
>

Cribbing from:

http://blog.stevex.net/index.php/c-c...5-hash-string/

The C# snippet is easily translated into PowerShell:

function Get-Md5
{
param ($inputString, $file, [switch] $base64)

if ($file)
{
$input = get-content -encoding byte -readcount -1 $file
}
else
{
$input = [System.Text.Encoding]::Unicode.GetBytes($inputString)
}
$md5 = [System.Security.Cryptography.MD5]::Create()
$output = $md5.ComputeHash($input)
if ($base64)
{
[System.Convert]::ToBase64String($output)
}
else
{
$sb = new-object Text.StringBuilder
foreach ($b in $output)
{
[void] $sb.Append($b.ToString("X2"));
}
$sb.ToString()
}
}

So when you're looking for a way to do something in PowerShell, C# and
VB.Net examples are also very useful :-)

-bruce

--
Bruce Payette [MSFT]
Windows PowerShell Technical Lead
Microsoft Corporation
This posting is provided "AS IS" with no warranties, and confers no rights.

Visit the Windows PowerShell Team blog at:
http://blogs.msdn.com/PowerShell
Visit the Windows PowerShell ScriptCenter at:
http://www.microsoft.com/technet/scr.../hubs/msh.mspx
My Book: http://manning.com/powershell

"Brandon Shell" <tshell.mask@gmail.com> wrote in message
news:O8szF3hGHHA.3468@TK2MSFTNGP04.phx.gbl...
> Ok... I got the MD5 from file (kinda simple really.)
>
> The problem is that this returns a Byte[]. Compare-Object doesn't like
> this for some reason and for seemingly obvious reasons .ToString() doesn't
> convert it correctly.
>
> Any Ideas?
>
> "Brandon Shell" <tshell.mask@gmail.com> wrote in message
> news:%23ciNSGhGHHA.1804@TK2MSFTNGP02.phx.gbl...
>> Goal: I want to be able to get the MD5 of file and store it. Then use it
>> to verify a file on a remote server is exactly the same.
>

Brandon Shell wrote:
> Ok... ignore me... I'm apparently prematurely asking for help. I figured it
> out.
>
well i had found the blog post for Get-MD5 by Marcel on old monad blog
site http://blogs.msdn.com/monad/archive/...13/465250.aspx .
I just could not ignore your post!

Thanks Bruce... I actually use that to get mine working. Mine is much
simpler... but I dont care about getting it to a string or file size.

"Bruce Payette [MSFT]" <brucepay@microsoft.com> wrote in message
news:usgAgKiGHHA.3464@TK2MSFTNGP05.phx.gbl...
> Cribbing from:
>
> http://blog.stevex.net/index.php/c-c...5-hash-string/
>
> The C# snippet is easily translated into PowerShell:
>
> function Get-Md5
> {
> param ($inputString, $file, [switch] $base64)
>
> if ($file)
> {
> $input = get-content -encoding byte -readcount -1 $file
> }
> else
> {
> $input = [System.Text.Encoding]::Unicode.GetBytes($inputString)
> }
> $md5 = [System.Security.Cryptography.MD5]::Create()
> $output = $md5.ComputeHash($input)
> if ($base64)
> {
> [System.Convert]::ToBase64String($output)
> }
> else
> {
> $sb = new-object Text.StringBuilder
> foreach ($b in $output)
> {
> [void] $sb.Append($b.ToString("X2"));
> }
> $sb.ToString()
> }
> }
>
> So when you're looking for a way to do something in PowerShell, C# and
> VB.Net examples are also very useful :-)
>
> -bruce
>
> --
> Bruce Payette [MSFT]
> Windows PowerShell Technical Lead
> Microsoft Corporation
> This posting is provided "AS IS" with no warranties, and confers no
> rights.
>
> Visit the Windows PowerShell Team blog at:
> http://blogs.msdn.com/PowerShell
> Visit the Windows PowerShell ScriptCenter at:
> http://www.microsoft.com/technet/scr.../hubs/msh.mspx
> My Book: http://manning.com/powershell
>
> "Brandon Shell" <tshell.mask@gmail.com> wrote in message
> news:O8szF3hGHHA.3468@TK2MSFTNGP04.phx.gbl...
>> Ok... I got the MD5 from file (kinda simple really.)
>>
>> The problem is that this returns a Byte[]. Compare-Object doesn't like
>> this for some reason and for seemingly obvious reasons .ToString()
>> doesn't convert it correctly.
>>
>> Any Ideas?
>>
>> "Brandon Shell" <tshell.mask@gmail.com> wrote in message
>> news:%23ciNSGhGHHA.1804@TK2MSFTNGP02.phx.gbl...
>>> Goal: I want to be able to get the MD5 of file and store it. Then use it
>>> to verify a file on a remote server is exactly the same.
>>
>
>

Hi Sung,

> well i had found the blog post for Get-MD5 by Marcel on old monad blog
> site http://blogs.msdn.com/monad/archive/...13/465250.aspx .
> I just could not ignore your post!

Nice! I modified the script a little bit so it handles powershell paths
correctly. It now also supports wildcards, piplining and an optional
format specifier:

PS > Get-MD5 *.ps1
PS > Get-MD5 *.ps1 -format D3
PS > ls -Recurse | Get-MD5
PS > ls -Recurse | Get-MD5 | Select Text, Path | ft -auto

cu

Max

# Get-MD5.ps1
param(
[string]$path,
[string]$format="X2")
begin
{
$hashAlgorithm = [System.Security.Cryptography.MD5]::Create()

function ProcessObject($object)
{
if($object -is [IO.FileInfo])
{
ProcessFile $object.FullName
}
elseif($object -is [IO.DirectoryInfo])
{
# skip directories...
}
elseif($object -and $object.Path)
{
ProcessFile $object.Path
}
elseif($object)
{
ProcessFile $object
}
}
function ProcessFile([string]$filesToProcess)
{
foreach($pathInfo in (resolve-path $filesToProcess))
{
$stream = $null;
trap
{
## We have to be sure that we close the file stream
## if any exceptions are thrown.
if ($stream -ne $null)
{
$stream.Close();
}
}

$file=[System.IO.FileInfo]$pathInfo.Path

$stream = $file.OpenRead();
$hashByteArray = $hashAlgorithm.ComputeHash($stream);
$stream.Close();

$result=1 | Select Text, Bytes, Path
$result.Text=[String]::Join("", ($hashByteArray | %{
"{0:$format}" -f $_ }) )
$result.Bytes=$hashByteArray
$result.Path=$file.FullName

$result
}
}
}
process
{
ProcessObject $_
}
end
{
ProcessObject $path
}
#eof

May I suggest that this get included in the Powershell Community Extensions?
Its very useful. Unfortunately for me I got this after I had written my
own... but I like yours better

"Maximilian Hänel" <ngSpam@smjh.de> wrote in message
news:OgyoaxkGHHA.3780@TK2MSFTNGP02.phx.gbl...
> Hi Sung,
>
>> well i had found the blog post for Get-MD5 by Marcel on old monad blog
>> site http://blogs.msdn.com/monad/archive/...13/465250.aspx .
>> I just could not ignore your post!
>
> Nice! I modified the script a little bit so it handles powershell paths
> correctly. It now also supports wildcards, piplining and an optional
> format specifier:
>
> PS > Get-MD5 *.ps1
> PS > Get-MD5 *.ps1 -format D3
> PS > ls -Recurse | Get-MD5
> PS > ls -Recurse | Get-MD5 | Select Text, Path | ft -auto
>
> cu
>
> Max
>
> # Get-MD5.ps1
> param(
> [string]$path,
> [string]$format="X2")
> begin
> {
> $hashAlgorithm = [System.Security.Cryptography.MD5]::Create()
>
> function ProcessObject($object)
> {
> if($object -is [IO.FileInfo])
> {
> ProcessFile $object.FullName
> }
> elseif($object -is [IO.DirectoryInfo])
> {
> # skip directories...
> }
> elseif($object -and $object.Path)
> {
> ProcessFile $object.Path
> }
> elseif($object)
> {
> ProcessFile $object
> }
> }
> function ProcessFile([string]$filesToProcess)
> {
> foreach($pathInfo in (resolve-path $filesToProcess))
> {
> $stream = $null;
> trap
> {
> ## We have to be sure that we close the file stream
> ## if any exceptions are thrown.
> if ($stream -ne $null)
> {
> $stream.Close();
> }
> }
>
> $file=[System.IO.FileInfo]$pathInfo.Path
>
> $stream = $file.OpenRead();
> $hashByteArray = $hashAlgorithm.ComputeHash($stream);
> $stream.Close();
>
> $result=1 | Select Text, Bytes, Path
> $result.Text=[String]::Join("", ($hashByteArray | %{
> "{0:$format}" -f $_ }) )
> $result.Bytes=$hashByteArray
> $result.Path=$file.FullName
>
> $result
> }
> }
> }
> process
> {
> ProcessObject $_
> }
> end
> {
> ProcessObject $path
> }
> #eof

Hi Bruce,

> $input = get-content -encoding byte -readcount -1 $file

Don't try this at home! ;-)
Reading the whole file into memory not only consumes lots of memory, it
might even fail on very large files.

cu

Max

Maximilian Hänel wrote:
> Hi Sung,
>
> > well i had found the blog post for Get-MD5 by Marcel on old monad blog
> > site http://blogs.msdn.com/monad/archive/...13/465250.aspx .
> > I just could not ignore your post!
>
> Nice! I modified the script a little bit so it handles powershell paths
> correctly. It now also supports wildcards, piplining and an optional
> format specifier:

Uhm.. Come to think of it, i did modify that Get-MD5 script a while
back
I had uploaded the my modification on www.CodePlex.com/psObject ...
Silly me.
My version supports checks against [FileInfo] though.. although it
supports pipeline input.
Looks quite similiar


# Author: Marcel Ortiz
# Modified by: Sung Kim
# Reference: http://blogs.msdn.com/monad/archive/...13/465250.aspx
# Description: Calculates the hash of a file and returns it as a
string.
# NOTE: Modified to act like a cmdlet to process pipeline input as well
# Original Get-MD5 by Marcel returns a string while this function
# returns a byte array per $file or a pipeline input
function Get-MD5 {
param([System.IO.FileInfo] $file)

begin {
function DisplayUsage {
$private:UsageString = 'USAGE: Get-MD5 [System.IO.FileInfo]`n'
$private:UsageString += 'Examples:`n'
$private:UsageString += '1) Get the MD5 bytes for the specified
argument`n'
$private:UsageString += '`tGet-MD5 (Get-Item file_name)`n'
$private:UsageString += '2) Get MD5 bytes for pipeline input`n'
$private:UsageString += '`tls | Get-MD5`n'
$private:UsageString += '3) How to check(a quick way) if two files
have same MD5 hash values`n'
$private:UsageString += '`tif (Compare-Object (get-md5 (gi
fileName1)) (get-md5 (gi fileName2))) `n'
$private:UsageString += '`t{ "different" } else { "same" }'
Write-Host -ForegroundColor "White" $private:UsageString
}

function ComputeHash([System.IO.FileInfo]$fileInfo) {
$PRIVATE:stream = $null;
# A type Shortcut for MD5CryptoServiceProvider type
# Reference:
http://blogs.msdn.com/powershell/arc...12/663540.aspx
$PRIVATE:cryptoServiceProvider =
[System.Security.Cryptography.MD5CryptoServiceProvider];
$PRIVATE:hashAlgorithm = new-object $PRIVATE:cryptoServiceProvider
$PRIVATE:stream = $fileInfo.OpenRead();
$PRIVATE:hashByteArray =
$PRIVATE:hashAlgorithm.ComputeHash($PRIVATE:stream);
$PRIVATE:stream.Close();

# We have to be sure that we close the file stream
# if any exceptions are thrown.
trap {
if ($PRIVATE:stream -ne $null) {
$PRIVATE:stream.Close();
}
break;
}

return $PRIVATE:hashByteArray;
}

}

process {
if ($_ -is [IO.FileInfo]) {
ComputeHash($_)
}
}

end {
# Check if "-?", "-h" or "-help" argument has been passed
if ($args[0] -match '-(\?|(h|(help)))') {
DisplayUsage
return;
}

if ($file) {
ComputeHash($file)
}

trap {
DisplayUsage;
break;
}
}
}