For all the Powershell noobs out there, including myself. Here is how to retrieve all the environment variables.
get-item -path env:*
For more info, check out this Technet article.
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Tag Archive for 'powershell'
The older I get, the more paranoid I get about things I download. Today I downloaded a freeware program from a 3rd party download site, since the publisher doesn’t actually allow downloading from their site. All they give is an MD5 checksum.
Well, I decided to write a quick Powershell script to do the checksum for me. (Got some pointers from another blog writing a cmd-let to do the same thing)
param ( $file ) $algo = [System.Security.Cryptography.HashAlgorithm]::Create("MD5") $stream = New-Object System.IO.FileStream($file, [System.IO.FileMode]::Open) $md5StringBuilder = New-Object System.Text.StringBuilder $algo.ComputeHash($stream) | % { [void] $md5StringBuilder.Append($_.ToString("x2")) } $md5StringBuilder.ToString() $stream.Dispose()
I probably should add a try/catch for the stream disposal and file existence validation. But, you get the picture.
I have read over Scott Hanselman’s Tool List at least a dozen times. The first time I read it, I saw that Powershell was on his top 10. I knew a little about Powershell from Exchange 2007 but hadn’t taken any time to look at it.
About a month ago, I had to write some server maintenance scripts. Things like deleting files older than X days, SQL Server maintenance, etc. These tasks were perfect for scripting, so I picked up a Powershell book and went to town. It took a while to pick it up, but my overall impression of Powershell is wow. Powershell fills that void in the soul of Windows that developers hate. Now scripting in Windows doesn’t have to involve Cygwin and Perl, even though Perl will always stay close to my heart.
Powershell combines the ease of scripting with the power of .NET. It is a loosely typed language that can work with strongly typed objects from .NET. For me, it boils down to scripting objects instead of text. In Bash, grep and awk had to be used when parsing the output of any program. In Powershell, the output of a program is usually an object, which is much easier to work with.
The following line sums up why I love Powershell. It deletes files older than 14 days in a directory. While this is a trivial example, it is so simple, and so elegant.
gci c:\directory | where { $_.LastWriteTime.AddDays(14) -lt [DateTime]::Now } | ri
Backing up a SQL Server database and restoring it to another server is a common operation done for reporting, testing, or development. When restoring on a different machine, a common problem is the login principals don’t actually correlate to the restored database users. This is because they are linked by an SID. This SID isn’t the user name, its some hash value, probably a GUID. The problem is fully described in this article.
Fixing the problem is really simple. Just run the following SQL and substitute
USE <database_name>; GO sp_change_users_login @Action='update_one', @UserNamePattern='<database_user>', @LoginName='<login_name>'; GO