When working with PowerShell I’m searching for the same variables over and over again. Every time when I found them again I think the same “Oh yeah, I knew that!”. To minimize my search next time I thought about writing it down.

First question, how do I use these variables? This is pretty straightforward.

```\$Env:username
```

Second question, which environment variables can I use? Use the following cmdlet:

```Get-Item Env: | sort Name

Name                           Value
----                           -----
COMPUTERNAME                   <computername>
HOMEPATH                       \Users\sa-sp2010-Install
LOCALAPPDATA                   C:\Users\sa-sp2010-Install\AppData\Local
PSModulePath                   D:\SPInstall\SPModule;D:\SPInstall\SPModule;C:\Users\sa-sp2010-Install\Documents\Windows...
PROCESSOR_ARCHITECTURE         AMD64
CommonProgramW6432             C:\Program Files\Common Files
CommonProgramFiles(x86)        C:\Program Files (x86)\Common Files
ProgramFiles(x86)              C:\Program Files (x86)
PROCESSOR_LEVEL                6
windows_tracing_flags          3
HOMEDRIVE                      C:
USERPROFILE                    C:\Users\sa-sp2010-Install
SystemRoot                     C:\Windows
TEMP                           C:\Users\SA-SP2~1\AppData\Local\Temp
PUBLIC                         C:\Users\Public
ALLUSERSPROFILE                C:\ProgramData
APPDATA                        C:\Users\sa-sp2010-Install\AppData\Roaming
ProgramData                    C:\ProgramData
PATHEXT                        .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
OS                             Windows_NT
CommonProgramFiles             C:\Program Files\Common Files
PROCESSOR_IDENTIFIER           Intel64 Family 6 Model 23 Stepping 10, GenuineIntel
ComSpec                        C:\Windows\system32\cmd.exe
SystemDrive                    C:
PROCESSOR_REVISION             170a
ProgramFiles                   C:\Program Files
NUMBER_OF_PROCESSORS           2
windows_tracing_logfile        C:\BVTBin\Tests\installpackage\csilogfile.log
TMP                            C:\Users\SA-SP2~1\AppData\Local\Temp
ProgramW6432                   C:\Program Files
Path                           C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPower...
USERDOMAIN                     <DOMAIN>
VS100COMNTOOLS                 C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\Tools\
windir                         C:\Windows             ```