Environmental Variables in Powershell

I have a script that I run in production that requires the script to access the Environment Variables for the server the script is executing on. This is a very simple task in powershell and very very useful. In my script I am using it just to verify that the machine name that it is executing on is the same as the machine name that I want the script to execute on. This is because the script is run from a single location and runs on many servers. The script compares the name that I am inputting to the actual machine name before moving on. Here is how easy this is in Powershell:

$name = (get-content env:Computername)

$name will now hold the value of the environmental variable on that machine for ComputerName. Powershell makes this so easy by having env as a PSDrive. This means that you can connect to it like you would a drive letter and get information from it. try the following:

cd env:

ls

and here is a sample of the results.

PS C:\Documents and Settings\smithco> cd env:
PS Env:\> ls

Name                           Value
—-                           —–
Path                           D:\oracle\ora92\bin;C:\Program Files\Oracle\jre\1.3.1\bin;C:\Program Files\Oracle\jre\1.1.8\bin;D:…
TEMP                           C:\DOCUME~1\smithco\LOCALS~1\Temp
SESSIONNAME                    Console
PATHEXT                        .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.PSC1
APPDATA                        C:\Documents and Settings\smithco\Application Data
SYBASE                         D:\Apps\sybase
PROCESSOR_ARCHITECTURE         x86
SystemDrive                    C:
HOMESHARE                      \\pni-pcfs01\HOME
DEFLOGDIR                      C:\Documents and Settings\All Users\Application Data\McAfee\DesktopProtection
windir                         C:\WINDOWS
USERPROFILE                    C:\Documents and Settings\smithco
TMP                            C:\DOCUME~1\smithco\LOCALS~1\Temp
SYBASE_JRE                     D:\Apps\sybase\shared-1_0\jre1.2.2
USERDNSDOMAIN                  PNI.US.AD.GANNETT.COM
USERDOMAIN                     PNI
ProgramFiles                   C:\Program Files
FP_NO_HOST_CHECK               NO
HOMEPATH                       \
COMPUTERNAME                   PNI-BT15689
CLASSPATH                      .;D:\Apps\sybase\ASEP_Win32\3pclass.zip;D:\Apps\sybase\ASEP_Win32\monclass.zip;C:\Program Files\Ja…
USERNAME                       smithco
NUMBER_OF_PROCESSORS           2
PROCESSOR_IDENTIFIER           x86 Family 15 Model 4 Stepping 3, GenuineIntel
VSEDEFLOGDIR                   C:\Documents and Settings\All Users\Application Data\McAfee\DesktopProtection
INCLUDE                        D:\Apps\sybase\OCS-12_5\include;
ComSpec                        C:\WINDOWS\system32\cmd.exe
LOGONSERVER                    \\PNI-DVADDC02
SYBASE_OCS                     OCS-12_5
CommonProgramFiles             C:\Program Files\Common Files
SystemRoot                     C:\WINDOWS
PROCESSOR_LEVEL                15
PROCESSOR_REVISION             0403
QTJAVA                         C:\Program Files\Java\jre1.6.0_05\lib\ext\QTJava.zip
lib                            D:\Apps\sybase\OCS-12_5\lib
ALLUSERSPROFILE                C:\Documents and Settings\All Users
WF_RESOURCES                   D:\oracle\ora92\WF\RES\WFus.RES
OS                             Windows_NT
HOMEDRIVE                      H:

PS Env:\>

Pretty cool huh….