Variables that customize the behavior of Windows PowerShell (about_preference_variables)
TOPICPreference VariablesSHORT DESCRIPTIONVariables that customize the behavior of Windows PowerShellLONG DESCRIPTIONWindows PowerShell includes a set of variables that enable you to customize its behavior. These "preference variables" work like the options in GUI-based systems. The preference variables affect the Windows PowerShell operating environment and all commands run in the environment. In many cases, the cmdlets have parameters that you can use to override the preference behavior for a specific command. The following table lists the preference variables and their default values. Variable Default Value -------- ------------- $ConfirmPreference High $DebugPreference SilentlyContinue $ErrorActionPreference Continue $ErrorView NormalView $FormatEnumerationLimit 4 $LogCommandHealthEvent False (not logged) $LogCommandLifecycleEvent False (not logged) $LogEngineHealthEvent True (logged) $LogEngineLifecycleEvent True (logged) $LogProviderLifecycleEvent True (logged) $LogProviderHealthEvent True (logged) $MaximumAliasCount 4096 $MaximumDriveCount 4096 $MaximumErrorCount 256 $MaximumFunctionCount 4096 $MaximumHistoryCount 64 $MaximumVariableCount 4096 $OFS (Space character (" ")) $OutputEncoding ASCIIEncoding object $ProgressPreference Continue $PSEmailServer (None) $PSSessionApplicationName WSMAN $PSSessionConfigurationName http://schemas.microsoft.com/powershell/microsoft.powershell $PSSessionOption (See below) $VerbosePreference SilentlyContinue $WarningPreference Continue $WhatIfPreference 0 Windows Powershell also includes the following environment variables that store user preferences. For more information about the environment variables, see about_environment_variables. Variable -------- PSModulePath WORKING WITH PREFERENCE VARIABLES This document describes each of the preference variables. To display the current value of a specific preference variable, type the name of the variable. In response, Windows PowerShell provides the value. For example, the following command displays the value of the $ConfirmPreference variable. PS> $ConfirmPreference High To change the value of a variable, use an assignment statement. For example, the following statement assigns the value "Medium" to the $ConfirmPreference variable. PS> $ConfirmPreference = "Medium" Like all variables, the values that you set are specific to the current Windows PowerShell window. To make them effective in all Windows PowerShell windows, add them to your Windows PowerShell profile. For more information, see about_profiles. WORKING REMOTELY When you run commands on a remote computer, the remote commands are subject only to the preferences set in the Windows PowerShell client on the remote computer. For example, when you run a remote command, the value of the $DebugPreference variable on remote computer determines how Windows PowerShell responds to debugging messages. For more information about remote commands, see about_remote. $ConfirmPreference ------------------ Determines which cmdlet actions automatically request confirmation from the user before they are performed. When the $ConfirmPreference value (High, Medium, Low, None) is greater than or equal to the risk of the cmdlet action (High, Medium, Low, None), Windows PowerShell automatically requests confirmation from the user before performing the action. You can use the Confirm parameter of a cmdlet to override the preference for a specific command. Valid values: None: No cmdlet actions are automatically confirmed. Users must use the Confirm parameter to request confirmation of specific commands. Low: Cmdlet actions with a low, medium, or high risk are automatically confirmed. To suppress confirmation of a specific command, use -Confirm:$false. Medium: Cmdlet actions with a medium or high risk are automatically confirmed. To enable confirmation of a specific command, use -confirm. To suppress confirmation of a specific command, use -confirm:$false. High: Cmdlet actions with a high risk are automatically (default) confirmed. To enable confirmation of a specific command, use -confirm. To suppress confirmation for a specific command, use -confirm:$false. DETAILED EXPLANATION When a cmdlet action significantly affects the system, such as by deleting data or by using a significant amount of system resources, Windows PowerShell can automatically prompt you for confirmation before performing the action. For example, PS> remove-item pref2.txt Confirm Are you sure you want to perform this action? Performing operation "Remove File" on Target "C:\pref2.txt". [Y] Yes [A] Yes to All [N] No [L] No to All [S] Suspend [?] Help (default is "Y"): The estimate of the risk is part of the cmdlet known as its "ConfirmImpact". You cannot change it. Cmdlet that might pose a risk to the system have a Confirm parameter that you can use to request or suppress confirmation for a specific command. Because most cmdlets use the default risk value of Medium, and the default value of $ConfirmPreference is High, automatic confirmation rarely occurs. However, you can activate automatic confirmation by changing the value of $ConfirmPreference to Medium or Low. EXAMPLES This example shows the effect of the default value of $ConfirmPreference. The High value only confirms high-risk cmdlet actions. Since most actions are of medium risk, they are not automatically confirmed, although you can use the Confirm parameter of the cmdlet to request confirmation of a specific command. PS> $confirmpreference #Get the current value of the High variable PS> remove-item temp1.txt #Delete a file PS> #Deleted without confirmation PS> remove-item temp2.txt -confirm #Use the Confirm parameter Confirm Are you sure you want to perform this action? Performing operation "Remove File" on Target "C:\temp2.txt". [Y] Yes [A] Yes to All [N] No [L] No to All [S] Suspend [?] Help (default is "Y"): This example shows the effect of changing the value of $ConfirmPrefernce to Medium. Because most cmdlet actions are medium-risk, they are automatically confirmed, and you have to use the Confirm parameter with a value of $false to suppress the confirmation prompt for a specific command. PS> $confirmpreference = "Medium" #Change the value of $ConfirmPreference PS> remove-item temp2.txt #Deleting a file triggers confirmation Confirm Are you sure you want to perform this action? Performing operation "Remove File" on Target "C:\temp2.txt". [Y] Yes [A] Yes to All [N] No [L] No to All [S] Suspend [?] Help (default is "Y"): PS> remove-item temp3.txt -confirm:$false #Use Confirm parameter to suppress confirmation PS> $DebugPreference ------------------ Determines how Windows PowerShell responds to debugging messages generated by a script, cmdlet or provider, or by a Write-Debug command at the command line. Some cmdlets display debugging messages, which are typically very technical messages designed for programmers and technical support professionals. By default, debugging messages are not displayed, but you can display debugging messages by changing the value of $DebugPreference. You can also use the Debug common parameter of a cmdlet to display or hide the debugging messages for a specific command. For more information, type: "get-help about_commonparameters". Valid values: Stop: Displays the debug message and stops executing. Writes an error to the console. Inquire: Displays the debug message and asks you whether you want to continue. Continue: Displays the debug message and continues with execution. SilentlyContinue: No effect. The debug message is not (Default) displayed and execution continues without interruption. EXAMPLES The following examples show the effect of changing the values of $DebugPreference when a Write-Debug command is entered at the command line. The change affects all debugging messages, including those generated by cmdlets and scripts. The examples also show the use of the Debug common parameter, which displays or hides the debugging messages related to a single command. This example shows the effect of the default value, "SilentlyContinue." The debug message is not displayed and processing continues. The final command uses the Debug parameter to override the preference for a single command. PS> $debugpreference # Get the current value of SilentlyContinue $DebugPreference PS> write-debug "Hello, World" PS> # The debug message is not displayed. PS> write-debug "Hello, World" -Debug # Use the Debug parameter DEBUG: Hello, World # The debug message is is requested. displayed and confirmation Confirm Continue with this operation? [Y] Yes [A] Yes to All [H] Halt Command [S] Suspend [?] Help (default is "Y"): This example shows the effect of the "Continue" value. The final command uses the Debug parameter with a value of $false to suppress the message for a single command. PS> $debugpreference = "Continue" # Change the value to "Continue" PS> write-debug "Hello, World" DEBUG: Hello, World # The debug message is displayed PS> and processing continues. PS> write-debug "Hello, World" -Debug:$false # Use the Debug parameter with false. PS> # The debug message is not displayed. This example shows the effect of the "Stop" value. The final command uses the Debug parameter with a value of $false to suppress the message for a single command. PS> $debugpreference = "Stop" #Change the value to "Stop" PS> write-debug "Hello, World" DEBUG: Hello, World Write-Debug : Command execution stopped because the shell variable "DebugPreference" is set to Stop. At line:1 char:12 + write-debug <<<< "Hello, World" PS> write-debug "Hello, World" -Debug:$false # Use the Debug parameter with $false PS> # The debug message is not displayed and processing is not stopped. This example shows the effect of the "Inquire" value. The final command uses the Debug parameter with a value of $false to suppress the message for a single command. PS> $debugpreference = "Inquire" PS> write-debug "Hello, World" DEBUG: Hello, World Confirm Continue with this operation? [Y] Yes [A] Yes to All [H] Halt Command [S] Suspend [?] Help (default is "Y"): PS> write-debug "Hello, World" -Debug:$false # Use the Debug parameter with $false PS> # The debug message is not displayed and processing continues without interruption. $ErrorActionPreference ---------------------- Determines how Windows PowerShell responds to a non-terminating error (an error that does not stop the cmdlet processing) at the command line or in a script, cmdlet, or provider, such as the errors generated by the Write-Error cmdlet. You can also use the ErrorAction common parameter of a cmdlet to override the preference for a specific command. For more information, type: "get-help about_commonparameters". Valid values: Stop: Displays the error message and stops executing. Inquire: Displays the error message and asks you whether you want to continue. Continue: Displays the error message and continues executing. SilentlyContinue: No effect. The error message is not (Default) displayed and execution continues without interruption. Neither $ErrorActionPreference nor the ErrorAction common parameter affect how Windows PowerShell responds to terminating errors (those that stop cmdlet processing). For more information about the ErrorAction common parameter, type "get-help about_commonparameters". EXAMPLES These examples show the effect of the different values of $ErrorActionPreference and the use of the ErrorAction common parameter to override the preference for a single command. The ErrorAction parameter has the same valid values as the $ErrorActionPreference variable. This example shows the effect of the Continue value, which is the default. PS> $erroractionpreference Continue # Display the value of the preference. PS> write-error "Hello, World" # Generate a non-terminating error. write-error "Hello, World" : Hello, World # The error message is displayed and execution continues. PS> write-error "Hello, World" -ErrorAction:SilentlyContinue # Use the ErrorAction parameter with a value of "SilentlyContinue". PS> # The error message is not displayed and execution continues. This example shows the effect of the SilentlyContinue value. PS> $ErrorActionPreference = "SilentlyContinue" # Change the value of the preference. PS> write-error "Hello, World" # Generate an error message. PS> # Error message is suppressed. PS> write-error "Hello, World" -erroraction:continue # Use the ErrorAction parameter with a value of "Continue". write-error "Hello, World" -erroraction:continue : Hello, World # The error message is displayed and execution continues. This example shows the effect of a real error. In this case, the command gets a non-existent file, nofile.txt. The example also uses the ErrorAction common parameter to override the preference. PS> $erroractionpreference SilentlyContinue # Display the value of the preference. PS> get-childitem -path nofile.txt PS> # Error message is suppressed. PS> $ErrorActionPreference = "Continue" # Change the value to Continue. PS> get-childitem -path nofile.txt Get-ChildItem : Cannot find path 'C:\nofile.txt' because it does not exist. At line:1 char:4 + get-childitem <<<< nofile.txt PS> get-childitem -path nofile.txt -erroraction SilentlyContinue # Use the ErrorAction parameter PS> # Error message is suppressed. PS> $ErrorActionPreference = "Inquire" # Change the value to Inquire. PS> get-childitem -path nofile.txt Confirm Cannot find path 'C:\nofile.txt' because it does not exist. [Y] Yes [A] Yes to All [H] Halt Command [S] Suspend [?] Help (default is "Y"): y Get-ChildItem : Cannot find path 'C:\nofile.txt' because it does not exist. At line:1 char:4 + get-childitem <<<< nofile.txt PS> $ErrorActionPreference = "Continue" # Change the value to Continue. PS> Get-Childitem nofile.txt -erroraction "Inquire" # Use the ErrorAction parameter to override the preference value. Confirm Cannot find path 'C:\nofile.txt' because it does not exist. [Y] Yes [A] Yes to All [H] Halt Command [S] Suspend [?] Help (default is "Y"): $ErrorView ---------- Determines the display format of error messages in Windows PowerShell. Valid values: NormalView: A detailed view designed for most users. (default) Consists of a description of the error, the name of the object involved in the error, and arrows (<<<<) that point to the words in the command that caused the error. CategoryView: A succinct, structured view designed for production environments. The format is: {Category}: ({TargetName}:{TargetType}):[{Activity}], {Reason} For more information about the fields in CategoryView, see "ErrorCategoryInfo class" in the Windows PowerShell SDK. EXAMPLES These example show the effect of the ErrorView values. This example shows how an error appears when the value of $ErrorView is NormalView. In this case, the Get-ChildItem command is used to find a non-existent file. PS> $ErrorView # Verify the value. NormalView PS> get-childitem nofile.txt # Find a non-existent file. Get-ChildItem : Cannot find path 'C:\nofile.txt' because it does not exist. At line:1 char:14 + get-childitem <<<< nofile.txt This example shows how the same error appears when the value of $ErrorView is CategoryView. PS> $ErrorView = "CategoryView" # Change the value to CategoryView PS> get-childitem nofile.txt ObjectNotFound: (C:\nofile.txt:String) [Get-ChildItem], ItemNotFoundException This example demonstrates that the value of ErrorView only affects the error display; it does not change the structure of the error object that is stored in the $error automatic variable. For information about the $error automatic variable, see about_automatic_variables. This command takes the ErrorRecord object associated with the most recent error in the error array (element 0) and formats all of the properties of the error object in a list. PS> $error[0] | format-list -property * -force Exception : System.Management.Automation.ItemNotFoundException: Cannot find path 'C:\nofile.txt' because it does not exist. at System.Management.Automation.SessionStateInternal.GetChildItems(String path, Boolean recurse, CmdletProviderContext context) at System.Management.Automation.ChildItemCmdletProviderIntrinsics.Get(String path, Boolean recurse, CmdletProviderContext context) at Microsoft.PowerShell.Commands.GetChildItemCommand.ProcessRecord() TargetObject : C:\nofile.txt CategoryInfo : ObjectNotFound: (C:\nofile.txt:String) [Get-ChildItem], ItemNotFoundException FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.GetChildItemCommand ErrorDetails : InvocationInfo : System.Management.Automation.InvocationInfo $FormatEnumerationLimit ----------------------- Determines how many enumerated items are included in a display. This variable does not affect the underlying objects; just the display. When the value of $FormatEnumerationLimit is less than the number of enumerated items, Windows PowerShell adds an ellipsis (...) to indicate items not shown. Valid values: Integers (Int32) Default value: 4 EXAMPLES This example shows how to use the $FormatEnumerationLimit variable to improve the display of enumerated items. The command in this example generates a table that lists all of the services running on the computer in two groups; one for running services and one for stopped services. It uses a Get-Service command to get all of the services, and then send the results through the pipeline to the Group-Object cmdlet, which groups the results by the service status. The resulting display is a table that lists the status in the Name column and the processes with that status in the Group column. (To change the column labels, use a hash table. For more information, see the examples in "get-help format-table -examples".) There are a maximum of 4 services listed in the Group column for each status. To increase the number of items listed, increase the value of $FormatEnumerationLimit to 1000. In the resulting display, the list in the Group column is now limited by the line length. In the final command in the example, use the Wrap parameter of Format-Table to display all of the processes in each Status group. PS> $formatenumerationlimit # Find the current value 4 PS> get-service | group-object -property status # List all services grouped by status Count Name Group ----- ---- ----- 60 Running {AdtAgent, ALG, Ati HotKey Poller, AudioSrv...} 41 Stopped {Alerter, AppMgmt, aspnet_state, ATI Smart...} # The list is truncated after 4 items. PS> $formatenumerationlimit = 1000 # Increase the limit to 1000. PS> get-service | group-object -property status # Repeat the command. Count Name Group ----- ---- ----- 60 Running {AdtAgent, ALG, Ati HotKey Poller, AudioSrv, BITS, CcmExec... 41 Stopped {Alerter, AppMgmt, aspnet_state, ATI Smart, Browser, CiSvc... PS> get-service | group-object -property status | format-table -wrap # Add the Wrap parameter. Count Name Group ----- ---- ----- 60 Running {AdtAgent, ALG, Ati HotKey Poller, AudioSrv, BITS, CcmExec, Client for NFS, CryptSvc, DcomLaunch, Dhcp, dmserver, Dnscache, ERSvc, Eventlog, EventSystem, FwcAgent, helpsvc, HidServ, IISADMIN, InoRPC, InoRT, InoTask, lanmanserver, lanmanworkstation, LmHosts, MDM, Netlogon, Netman, Nla, NtLmSsp, PlugPlay, PolicyAgent, ProtectedStorage, RasMan, RemoteRegistry, RpcSs, SamSs, Schedule, seclogon, SENS, SharedAccess, ShellHWDetection, SMT PSVC, Spooler, srservice, SSDPSRV, stisvc, TapiSrv, TermService, Themes, TrkWks, UMWdf, W32Time, W3SVC, WebClient, winmgmt, wscsvc, wuauserv, WZCSVC, zzInterix} 41 Stopped {Alerter, AppMgmt, aspnet_state, ATI Smart, Browser, CiSvc, ClipSrv, clr_optimization_v2.0.50727_32, COMSysApp, CronService, dmadmin, FastUserSwitchingCompatibility, HTTPFilter, ImapiService, Mapsvc, Messenger, mnmsrvc, MSDTC, MSIServer, msvsmon80, NetDDE, NetDDEdsdm, NtmsSvc, NVSvc, ose, RasAuto, RDSessMgr, RemoteAccess, RpcLocator, RSVP, SCardSvr, SwPrv, SysmonLog, TlntSvr, upnphost, UPS, VSS, WmdmPmSN, Wmi, WmiApSrv, xmlprov} $Log*Event ---------- The Log*Event preference variables determine which types of events are written to the Windows PowerShell event log in Event Viewer. By default, only engine and provider events are logged, but you can use the Log*Event preference variables to customize your log, such as logging events about commands. The Log*Event preference variables are as follows: $LogCommandHealthEvent: Logs errors and exceptions in command initialization and processing. Default = $false (not logged). $LogCommandLifecycleEvent: Logs the starting and stopping of commands and command pipelines and security exceptions in command discovery. Default = $false (not logged). $LogEngineHealthEvent: Logs errors and failures of sessions. Default = $true (logged). $LogEngineLifecycleEvent: Logs the opening and closing of sessions. Default = $true (logged). $LogProviderHealthEvent: Logs provider errors, such as read and write errors, lookup errors, and invocation errors. Default = $true (logged). $LogProviderLifecycleEvent: Logs adding and removing of Windows PowerShell providers. Default = $true (logged). (For information about Windows PowerShell providers, type: "get-help about_provider". To enable a Log*Event, type the variable with a value of $true, for example: $LogCommandLifeCycleEvent - or - $LogCommandLifeCycleEvent = $true To disable an event type, type the variable with a value of $false, for example: $LogCommandLifeCycleEvent = $false The events that you enable are effective only for the current Windows PowerShell console. To apply the configuration to all consoles, save the variable settings in your Windows PowerShell profile. $MaximumAliasCount ------------------ Determines how many aliases are permitted in a Windows PowerShell session. The default value, 4096, should be sufficient for most uses, but you can adjust it to meet your needs. Valid values: 1024 - 32768 (Int32) Default: 4096 To count the aliases on your system, type: (get-alias).count $MaximumDriveCount ------------------ Determines how many Windows PowerShell drives are permitted in a given session. This includes file system drives and data stores that are exposed by Windows PowerShell providers and appear as drives, such as the Alias: and HKLM: drives. Valid values: 1024 - 32768 (Int32) Default: 4096 To count the aliases on your system, type: (get-psdrive).count $MaximumErrorCount ------------------ Determines how many errors are saved in the error history for the session. Valid values: 256 - 32768 (Int32) Default: 256 Objects that represent each retained error are stored in the $Error automatic variable. This variable contains an array of error record objects, one for each error. The most recent error is the first object in the array ($Error[0]). To count the errors on your system, use the Count property of the $Error array. Type: $Error.count To display a specific error, use array notation to display the error. For example, to see the most recent error, type: $Error[0] To display the oldest retained error, type: $Error[($Error.Count -1] To display the properties of the ErrorRecord object, type: $Error[0] | format-list -property * -force In this command, the Force parameter overrides the special formatting of ErrorRecord objects and reverts to the conventional format. To delete all errors from the error history, use the Clear method of the error array. PS> $Error.count 17 PS> $Error.clear() PS> PS> $Error.count 0 To find all properties and methods of an error array, use the Get-Member cmdlet with its InputObject parameter. When you pipe a collection of objects to Get-Member, Get-Member displays the properties and methods of the objects in the collection. When you use the InputObject parameter of Get-Member, Get-Member displays the properties and methods of the collection. $MaximumFunctionCount ------------------ Determines how many functions are permitted in a given session. Valid values: 1024 - 32768 (Int32) Default: 4096 To see the functions in your session, use the Windows PowerShell Function: drive that is exposed by the Windows PowerShell Function provider. (For more information about the Function provider, type "get-help function"). To list the functions in the current session, type: get-childitem function: To count the functions in the current session, type: (get-childitem function:).count $MaximumHistoryCount ------------------ Determines how many commands are saved in the command history for the current session. Valid values: 1 - 32768 (Int32) Default: 64 To determine the number of commands current saved in the command history, type: (get-history).count To see the command saved in your session history, use the Get-History cmdlet. For more information, type: "get-help about_history". $MaximumVariableCount ------------------ Determines how many variables are permitted in a given session, including automatic variables, preference variables, and the variables that you create in commands and scripts. Valid values: 1024 - 32768 (Int32) Default: 4096 To see the variables in your session, use the Get-Variable cmdlet and the features of the Windows PowerShell Variable: drive and the Windows PowerShell Variable provider. For information about the Variable provider, type "get-help variable". To find the current number of variables on the system, type: (get-variable).count $OFS ---- Output Field Separator. Specifies the character that separates the elements of an array when the array is converted to a string. Valid values: Any string. Default: Space By default, the $OFS variable does not exist and the output file separator is a space, but you can add this variable and set it to any string. EXAMPLES This example shows that a space is used to separate the values when an array is converted to a string. In this case, an array of integers is stored in a variable and then the variable is cast as a string. PS> $array = 1,2,3 # Store an array of integers. PS> [string]$array # Cast the array to a string. 1 2 3 # Spaces separate the elements To change the separator, add the $OFS variable by assigning a value to it. To work correctly, the variable must be named $OFS. PS> $OFS = "+" # Create $OFS and assign a "+" PS> [string]$array # Repeat the command 1+2+3 # Plus signs separate the elements To restore the default behavior, you can assign a space (" ") to the value of $OFS or delete the variable. This command deletes the variable and then verifies that the separator is a space. PS> Remove-Variable OFS # Delete $OFS PS> PS> [string]$array # Repeat the command 1 2 3 # Spaces separate the elements $OutputEncoding --------------- Determines the character encoding method used by Windows PowerShell when it sends text to other applications. For example, if an application returns Unicode strings to Windows PowerShell, you might need to change the value to to send the characters correctly. Valid values: Objects derived from an encoding class, such as ASCIIEncoding, SBCSCodePageEncoding, UTF7Encoding, UTF8Encoding, UTF32Encoding, and UnicodeEncoding. Default: ASCIIEncoding object (System.Text.ASCIIEncoding) EXAMPLES This example shows how to make the FINDSTR command in Windows work in Windows PowerShell on a computer that is localized for a language that uses Unicode characters, such as Chinese. The first command finds the value of $OutputEncoding. Because the value is an encoding object, display only its EncodingName property. PS> $OutputEncoding.EncodingName # Find the current value US-ASCII In this example, a FINDSTR command is used to search for two Chinese characters that are present in the Test.txt file. When this FINDSTR command is run in the Windows Command Prompt (Cmd.exe), FINDSTR finds the characters in the text file. However, when you run the same FINDSTR command in Windows PowerShell, the characters are not found because the Windows PowerShell sends them to FINDSTR in ASCII text, instead of in Unicode text. PS> findstr <Unicode-characters> # Use findstr to search. PS> # None found. To make the command work in Windows PowerShell, set the value of $OutputEncoding to the value of the OutputEncoding property of the console, which is based on the locale selected for Windows. Because OutputEncoding is a static property of the console, use double-colons (::) in the command. PS> $OutputEncoding = [console]::outputencoding PS> # Set the value equal to the OutputEncoding property of the console. PS> $OutputEncoding.EncodingName OEM United States # Find the resulting value. As a result of this change, the FINDSTR command finds the characters. PS> findstr <Unicode-characters> test.txt: <Unicode-characters> # Use findstr to search. It find the characters in the text file. $ProgressPreference ------------------- Determines how Windows PowerShell responds to progress updates generated by a script, cmdlet or provider, such as the progress bars generated by the Write-Progress cmdlet. The Write-Progress cmdlet creates progress bars that depict the status of a command. Valid values: Stop: Does not display the progress bar. Instead, it displays an error message and stops executing. Inquire: Does not display the progress bar. Prompts for permission to continue. If you reply with Y or A, it displays the progress bar. Continue: Displays the progress bar and continues with (Default) execution. SilentlyContinue: Executes the command, but does not display the progress bar. $PSEmailServer -------------- Specifies the default e-mail server that is used to send e-mail messages. This preference variable is used by cmdlets that send e-mail, such as the Send-MailMessage cmdlet. $PSSessionApplicationName --------------------------- Specifies the default application name for a remote command that uses WS-Management technology. The system default application name is WSMAN, but you can use this preference variable to change the default. The application name is the last node in a connection URI. For example, the application name in the following sample URI is WSMAN. http://Server01:8080/WSMAN The default application name is used when the remote command does not specify a connection URI or an application name. The WinRM service uses the application name to select a listener to service the connection request. The value of this parameter should match the value of the URLPrefix property of a listener on the remote computer. To override the system default and the value of this variable, and select a different application name for a particular session, use the ConnectionURI or ApplicationName parameters of the New-PSSession, Enter-PSSession or Invoke-Command cmdlets. This preference variable is set on the local computer, but it specifies a listener on the remote computer. If the application name that you specify does not exist on the remote computer, the command to establish the session fails. $PSSessionConfigurationName --------------------------- Specifies the default session configuration that is used for PSSessions created in the current session. This preference variable is set on the local computer, but it specifies a session configuration that is located on the remote computer. The value of the $PSSessionConfigurationName variable is a fully qualified resource URI. The default value: http://schemas.microsoft.com/powershell/microsoft.powershell indicates the Microsoft.PowerShell session configuration on the remote computer. If you specify only a configuration name, the following schema URI is prepended: http://schemas.microsoft.com/powershell/ You can override the default and select a different session configuration for a particular session by using the ConfigurationName parameter of the New-PSSession, Enter-PSSession or Invoke-Command cmdlets. You can change the value of this variable at any time. When you do, remember that the session configuration that you select must exist on the remote computer. If it does not, the command to create a session that uses the session configuration fails. This preference variable does not determine which local session configurations are used when remote users create a session that connects to this computer. However, you can use the permissions for the local session configurations to determine which users may use them. $PSSessionOption ---------------- Establishes the default values for advanced user options in a remote session. These option preferences override the system default values for session options. You can also set custom options for a particular remote session by using the SessionOption parameter in cmdlets that create a session, such as New-PSSession, Enter-PSSession, and Invoke-Command. The SessionOption parameter value takes precedence over the system defaults and the defaults that are set in this variable. The $PSSessionOption variable contains a PSSessionOption object (System.Management.Automation.Remoting.PSSessionObject). Each property of the object represents a session option. For example, the NoCompression property turns of data compression during the session. To create the $PSSessionOption preference variable, use the New-PSSessionOption cmdlet. Save the output in a variable called $PSSessionOption. For example, $PSSessionOption = New-PSSessionOption -NoCompression To use the $PSSessionOption preference variable in every Windows PowerShell session, add a New-PSSessionOption command that creates the $PSSessionOption variable to your Windows PowerShell profile. For more information about the New-PSSessionOption cmdlet, see the help topic for New-PSSessionOption. For more information about remote commands and sessions, see about_Remote and about_PSSessions. For more information about using a profile, see about_Profiles. $VerbosePreference ------------------ Determines how Windows PowerShell responds to verbose messages generated by a script, cmdlet or provider, such as the messages generated by the Write-Verbose cmdlet. Typically, verbose messages describe the actions performed to execute a command. By default, verbose messages are not displayed, but you can change this behavior by changing the value of $VerbosePreference. You can also use the Verbose common parameter of a cmdlet to display or hide the verbose messages for a specific command. For more information, type: "get-help about_commonparameters". Valid values: Stop: Displays the verbose message and an error message and then stops executing. Inquire: Displays the verbose message and then displays a prompt that asks you whether you want to continue. Continue: Displays the verbose message and then continues with execution. SilentlyContinue: Does not display the verbose message. Continues executing. (Default) EXAMPLES These examples show the effect of the different values of $VerbosePreference and the use of the Verbose common parameter to override the preference value. This example shows the effect of the SilentlyContinue value, which is the default. PS> $VerbosePreference # Find the current value. SilentlyContinue PS> Write-Verbose "Verbose message test." PS> # Write a verbose message. # Message is not displayed. PS> Write-Verbose "Verbose message test." -verbose VERBOSE: Verbose message test. # Use the Verbose parameter. This example shows the effect of the Continue value. PS> $VerbosePreference = "Continue" # Change the value to Continue. PS> Write-Verbose "Verbose message test." # Write a verbose message. VERBOSE: Verbose message test. # Message is displayed. PS> Write-Verbose "Verbose message test." -verbose:$false # Use the Verbose parameter with a value of $false. PS> # Message is not displayed. This example shows the effect of the Stop value. PS> $VerbosePreference = "Stop" # Change the value to Stop. PS> Write-Verbose "Verbose message test." # Write a verbose message. VERBOSE: Verbose message test. Write-Verbose : Command execution stopped because the shell variable "VerbosePreference" is set to Stop. At line:1 char:14 + Write-Verbose <<<< "Verbose message test." PS> Write-Verbose "Verbose message test." -verbose:$false # Use the Verbose parameter with a value of $false PS> # Message is not displayed. This example shows the effect of the Inquire value. PS> $VerbosePreference = "Inquire" # Change the value to Inquire. PS> Write-Verbose "Verbose message test." VERBOSE: Verbose message test. # Write a verbose message. Confirm Continue with this operation? [Y] Yes [A] Yes to All [H] Halt Command [S] Suspend [?] Help (default is "Y"): y PS> PS> Write-Verbose "Verbose message test." -verbose:$false # Use the Verbose parameter. PS> # Message is not displayed. $WarningPreference ------------------ Determines how Windows PowerShell responds to warning messages generated by a script, cmdlet or provider, such as the messages generated by the Write-Warning cmdlet. By default, warning messages are displayed and execution continues, but you can change this behavior by changing the value of $WarningPreference. You can also use the WarningAction common parameter of a cmdlet to determine how Windows PowerShell responds to warnings from a particular command. For more information, type: "get-help about_commonparameters". Valid values: Stop: Displays the warning message and an error message and then stops executing. Inquire: Displays the warning message and then prompts for permission to continue. Continue: Displays the warning message and then (Default) continues executing. SilentlyContinue: Does not display the warning message. Continues executing. EXAMPLES These examples show the effect of the different values of $WarningPreference and the use of the WarningAction common parameter to override the preference value. This example shows the effect of the Continue value, which is the default. PS> $WarningPreference # Find the current value. Continue # Write a warning message. PS> Write-Warning "This action can delete data." WARNING: This action can delete data. # Use the WarningAction parameter to # suppress the warning for this command PS> Write-Warning "This action can delete data." -warningaction silentlycontinue This example shows the effect of the SilentlyContinue value. PS> $WarningPreference = "SilentlyContinue" # Change the value to SilentlyContinue. PS> Write-Warning "This action can delete data." PS> # Write a warning message. PS> Write-Warning "This action can delete data." -warningaction stop # Use the WarningAction parameter to stop # processing when this command generates a # warning. WARNING: This action can delete data. Write-Warning : Command execution stopped because the shell variable "WarningPreference" is set to Stop. At line:1 char:14 + Write-Warning <<<< "This action can delete data." -warningaction stop This example shows the effect of the Inquire value. PS> $WarningPreference = "Inquire" # Change the value to Inquire. PS> Write-Warning "This action can delete data." # Write a warning message. WARNING: This action can delete data. Confirm Continue with this operation? [Y] Yes [A] Yes to All [H] Halt Command [S] Suspend [?] Help (default is "Y"): y PS> PS> Write-Warning "This action can delete data." -warningaction silentlycontinue PS> # Use the WarningAction parameter to change the # response to a warning for the current command. This example shows the effect of the Stop value. PS> $WarningPreference = "Stop" # Change the value to Stop. PS> Write-Warning "This action can delete data." # Write a warning message. WARNING: This action can delete data. Write-Warning : Command execution stopped because the shell variable "WarningPreference" is set to Stop. At line:1 char:14 + Write-Warning <<<< "This action can delete data." PS> Write-Warning "This action can delete data." -warningaction inquire WARNING: This action can delete data. Confirm Continue with this operation? [Y] Yes [A] Yes to All [H] Halt Command [S] Suspend [?] Help (default is "Y"): # Use the WarningAction parameter to change the # response to a warning for the current command. $WhatIfPreference ------------------ Determines whether WhatIf is automatically enabled for every command that supports it. When WhatIf is enabled, the cmdlet reports the expected effect of the command, but does not execute the command. Valid values: 0: WhatIf is not automatically enabled. To (Default) enable it manually, use the WhatIf parameter of the command. 1: WhatIf is automatically enabled on any command that supports it. Users can use the WhatIf command with a value of False to disable it manually (WhatIf:$false). DETAILED EXPLANATION When a cmdlet supports WhatIf, the cmdlet reports the expected effect of the command, instead of executing the command. For example, instead of deleting the test.txt file in response to a Remove-Item command, Windows PowerShell reports what it would delete. A subsequent Get-Childitem command confirms that the file was not deleted. PS> remove-item test.txt What if: Performing operation "Remove-Item" on Target "Item: C:\test.txt PS> get-childitem test.txt Directory: Microsoft.PowerShell.Core\FileSystem::C: Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 7/29/2006 7:15 PM 84 test.txt EXAMPLES These examples show the effect of the different values of $WhatIfPreference. They also show how to use the WhatIf cmdlet parameter to override the preference value for a specific command. This example shows the effect of the 0 (not enabled) value, which is the default. PS> $whatifpreference 0 # Check the current value. PS> get-childitem test.txt | format-list FullName FullName : C:\test.txt # Verify that the file exists. PS> remove-item test.txt PS> # Delete the file. PS> get-childitem test.txt | format-list -property FullName # Verify that the file is deleted. Get-ChildItem : Cannot find path 'C:\test.txt' because it does not exist. At line:1 char:14 + get-childitem <<<< test.txt | format-list fullname This example shows the effect of using the WhatIf parameter when the value of $WhatIfPreference is 0. PS> get-childitem test2.txt | format-list -property FullName FullName : C:\test2.txt # Verify that the file exists. PS> remove-item test2.txt -whatif What if: Performing operation "Remove File" on Target "C:\test2.txt". # Use the WhatIf parameter PS> get-childitem test2.txt | format-list -property FullName FullName : C:\test2.txt # Verify that the file was not deleted This example shows the effect of the 1 (WhatIf enabled) value. When you use Remove-Item to delete a cmdlet, Remove-Item displays the path to the file that it would delete, but it does not delete the file. PS> $whatifpreference = 1 PS> $whatifpreference 1 # Change the value. PS> remove-item test.txt What if: Performing operation "Remove File" on Target "C:\test.txt". # Try to delete a file. PS> get-childitem test.txt | format-list FullName FullName : C:\test.txt # Verify that the file exists. This example shows how to delete a file when the value of $WhatIfPreference is 1. It uses the WhatIf parameter with a value of $false. PS> remove-item test.txt -whatif:$false # Use the WhatIf parameter with $false. This example demonstrates that some cmdlets support WhatIf behavior and others do not. In this example, in which the value of $WhatIfPreference is 1 (enabled), a Get-Process command, which does not support WhatIf, is executed, but a Stop-Process command performs the WhatIf behavior. You can override the WhatIf behavior of the Stop-Process command by using the WhatIf parameter with a value of $false. PS> $whatifpreference = 1 # Change the value to 1. PS> get-process winword # A Get-Process command completes. Handles NPM(K) PM(K) WS(K) VM(M) CPU(s) Id ProcessName ------- ------ ----- ----- ----- ------ -- ----------- 234 8 6324 15060 154 0.36 2312 WINWORD PS> stop-process -name winword What if: Performing operation "Stop-Process" on Target "WINWORD (2312)". # A Stop-Process command uses WhatIf. PS> stop-process -name winword -whatif:$false PS> # WhatIf:$false overrides the preference. PS> get-process winword Get-Process : Cannot find a process with the name 'winword'. Verify the process name and call the cmdlet again. At line:1 char:12 + get-process <<<< winword # Verify that the process is stopped. SEE ALSO about_Automatic_Variables about_CommonParameters about_Environment_Variables about_Profiles about_Remote about_Scopes about_Variables C:\Windows>powershell get-help about_profiles -full
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ColorConsole [Version 3.7.1000] PowerShell 2.0-Export
