Microsoft Exchange Server 2007 Administrators Pocket Consultant Second Edition
Cmdlets provide the basic foundation for working with a computer from within the Windows PowerShell. Although there are many different cmdlets with many different available uses, cmdlets all have common features. I'll examine these common features in this section.
Using Windows PowerShell Cmdlets
At the Windows PowerShell prompt, you can get a complete list of cmdlets available by typing help *-*. To get help documentation on a specific cmdlet, type help followed by the cmdlet name, such as:
help get-variable
Table 6-2 provides a list of cmdlets you'll commonly use for administration. Although there are many other cmdlets available, these are the ones you're likely to use the most.
| Cmdlet Name | Description |
|---|---|
| ConvertFrom-SecureString | Export a secure string to a safe format. |
| ConvertTo-SecureString | Create a securestring from a normal string. |
| Get-Alias | Returns alias names for cmdlets. |
| Get-AuthenticodeSignature | Gets the signature object associated with a file. |
| Get-Credential | Gets a credential object based on a password. |
| Get-Date | Gets the current date and time. |
| Get-EventLog | Gets the log data from the Windows log files. |
| Get-ExecutionPolicy | Gets the effective execution policy for the current shell. |
| Get-Host | Gets host information. |
| Get-Location | Displays the current location. |
| Get-MshDrive | Gets the drive information for the specified Msh drive. |
| Get-Service | Gets a list of services. |
| Import-Alias | Imports an alias list from a file. |
| New-Alias | Creates a new cmdlet-alias pairing. |
| New-Service | Creates a new service. |
| Push-Location | Pushes a location to the stack. |
| Read-Host | Reads a line of input from the host console. |
| Restart-Service | Restarts a stopped service. |
| Resume-Service | Resumes a suspended service. |
| Set-Alias | Maps an alias to a cmdlet. |
| Set-AuthenticodeSignature | Places an Authenticode signature in a script or other file. |
| Set-Date | Sets the system date and time on the host system. |
| Set-ExecutionPolicy | Sets the execution policy for the current shell. |
| Set-Location | Sets the current working location to a specified location. |
| Set-Service | Makes and sets changes to the properties of a service. |
| Start-Service | Starts a stopped service. |
| Start-Sleep | Suspends shell or script activity for the specified period. |
| Stop-Service | Stops a running service. |
| Suspend-Service | Suspends a running service. |
| Write-Output | Writes an object to the pipeline. |
Using Cmdlet Parameters
All cmdlet parameters are designated with an initial dash (-). To reduce the amount of typing required, some parameters are position-sensitive such that you can sometimes pass parameters in a specific order without having to specify the parameter name. For example, with get-service, you don't have to specify the -Name parameter, you can simply type:
Get-service ServiceName
where ServiceName is the name of the service you want to examine, such as:
Get-service MSExchangeIS
This command line returns the status of the Microsoft Exchange Information Store service. Because you can use wildcards, such as *, with name values, you can also type get-service mse* to return the status of all Microsoft Exchange–related services.
All cmdlets support the common set of parameters listed in Table 6-3. However, for you to use these parameters, you must run the cmdlet in such a way that these parameters are returned as part of the result set.
| Parameter Name | Description |
|---|---|
| -Confirm | Pauses processes and requires the user to acknowledge the action before continuing. Remove- and Disable- cmdlets have this parameter. |
| -Debug | Provides programming-level debugging information about the operation. |
| -ErrorAction | Controls the command behavior when an error occurs. |
| -ErrorVariable | Sets the name of the variable (in addition to the standard error) in which to place objects for which an error has occurred. |
| -OutBuffer | Sets the output buffer for the cmdlet. |
| -OutVariable | Sets the name of the variable in which to place output objects. |
| -Verbose | Provides detailed information about the operation. |
| -WhatIf | Allows the user to view what would happen if a cmdlet were run with a specific set of parameters. Remove- and Disable- cmdlets have this parameter. |
Understanding Cmdlet Errors
When you work with cmdlets, you'll encounter two standard types of errors:
-
Terminating errors Errors that halt execution
-
Nonterminating errors Errors that cause error output to be returned but do not halt execution
With both types of errors, you'll typically see error text that can help you resolve the problem. For example, an expected file might be missing, or you may not have sufficient permissions to perform a specified task.
Using Cmdlet Aliases
For ease of use, Windows PowerShell lets you create aliases for cmdlets. An alias is an abbreviation for a cmdlet that acts as a shortcut for executing the cmdlet. For example, you can use the alias gsv instead of the cmdlet name get-service.
Table 6-4 provides a list of commonly used default aliases. Although there are many other aliases, these are the ones you'll use most frequently.
| Alias | Cmdlet |
|---|---|
| clear, cls | Clear-Host |
| Diff | Compare-Object |
| cp, copy | Copy-Item |
| Epal | Export-Alias |
| Epcsv | Export-Csv |
| Foreach | ForEach-Object |
| Fl | Format-List |
| Ft | Format-Table |
| Fw | Format-Wide |
| Gal | Get-Alias |
| ls, dir | Get-ChildItem |
| Gcm | Get-Command |
| cat, type | Get-Content |
| h, history | Get-History |
| gl, pwd | Get-Location |
| gps, ps | Get-Process |
| Gsv | Get-Service |
| Gv | Get-Variable |
| Group | Group-Object |
| Ipal | Import-Alias |
| Ipcsv | Import-Csv |
| R | Invoke-History |
| Ni | New-Item |
| Mount | New-MshDrive |
| Nv | New-Variable |
| rd, rm, rmdir, del, erase | Remove-Item |
| Rv | Remove-Variable |
| Sal | Set-Alias |
| sl, cd, chdir | Set-Location |
| sv, set | Set-Variable |
| Sort | Sort-Object |
| Sasv | Start-Service |
| Sleep | Start-Sleep |
| spps, kill | Stop-Process |
| Spsv | Stop-Service |
| write, echo | Write-Output |
You can define additional aliases using the Set-Alias cmdlet. The syntax is:
Set-alias aliasName cmdletName
Where aliasName is the alias you want to use and cmdletName is the cmdlet for which you are creating an alias. The following example creates a "go" alias for the get-process cmdlet:
Set-alias go get-process
To use your custom aliases whenever you work with Windows PowerShell, enter the related command line in your profile.
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