Powershell – Running a command as Administrator using PowerShell

If, some time during a PowerShell session, you need to append to the PATH environment variable temporarily, you can do it this way:

$env:Path += ";C:\Program Files\GnuWin32\bin"

If you need your path to be called before standard one, insert it at the beginning

$env:Path = "C:\Program Files\GnuWin32\bin;$env:Path"

When PowerShell sees a command starting with a string it just evaluates the string, that is, it typically echos it to the screen, for example:

PS> "Hello World"
Hello World

If you want PowerShell to interpret the string as a command name then use the call operator (&) like so:

PS> & 'C:\Program Files\IIS\Microsoft Web Deploy\msdeploy.exe'

After that you probably only need to quote parameter/argument pairs that contain spaces and/or quotation chars. When you invoke an EXE file like this with complex command line arguments it is usually very helpful to have a tool that will show you how PowerShell sends the arguments to the EXE file. The PowerShell Community Extensions has such a tool. It is called echoargs. You just replace the EXE file with echoargs - leaving all the arguments in place, and it will show you how the EXE file will receive the arguments, for example:

PS> echoargs -verb:sync -source:dbfullsql="Data Source=mysource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;" -dest:dbfullsql="Data Source=.\mydestsource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;",computername=10.10.10.10,username=administrator,password=adminpass

Arg 0 is <-verb:sync>
Arg 1 is <-source:dbfullsql=Data>
Arg 2 is <Source=mysource;Integrated>
Arg 3 is <Security=false;User>
Arg 4 is <ID=sa;Pwd=sapass!;Database=mydb;>
Arg 5 is <-dest:dbfullsql=Data>
Arg 6 is <Source=.\mydestsource;Integrated>
Arg 7 is <Security=false;User>
Arg 8 is <ID=sa;Pwd=sapass!;Database=mydb; computername=10.10.10.10 username=administrator password=adminpass>

Using echoargs you can experiment until you get it right, for example:

PS> echoargs -verb:sync "-source:dbfullsql=Data Source=mysource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;"
Arg 0 is <-verb:sync>
Arg 1 is <-source:dbfullsql=Data Source=mysource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;>

It turns out I was trying too hard before to maintain the double quotes around the connection string. Apparently that isn't necessary because even cmd.exe will strip those out.

BTW, hats off to the PowerShell team. They were quite helpful in showing me the specific incantation of single & double quotes to get the desired result - if you needed to keep the internal double quotes in place. :-) They also realize this is an area of pain, but they are driven by the number of folks are affected by a particular issue. If this is an area of pain for you, then please vote up this PowerShell bug submission.

For more information on how PowerShell parses, check out my Effective PowerShell blog series - specifically item 10 - "Understanding PowerShell Parsing Modes"

UPDATE 4/4/2012: This situation gets much easier to handle in PowerShell V3. See this blog post for details.