Restart-Computer

Module:
Microsoft.PowerShell.Management
Restarts ("reboots") the operating system on local and remote computers.

Syntax 

Restart-Computer
       [-DcomAuthentication <AuthenticationLevel>]
       [-Impersonation <ImpersonationLevel>]
       [-WsmanAuthentication <String>]
       [-Protocol <String>]
       [[-ComputerName] <String[]>]
       [[-Credential] <PSCredential>]
       [-Force]
       [-Wait]
       [-Timeout <Int32>]
       [-For <WaitForServiceTypes>]
       [-Delay <Int16>]
       [-WhatIf]
       [-Confirm]
       [<CommonParameters>]
Restart-Computer
       [-AsJob]
       [-DcomAuthentication <AuthenticationLevel>]
       [-Impersonation <ImpersonationLevel>]
       [[-ComputerName] <String[]>]
       [[-Credential] <PSCredential>]
       [-Force]
       [-ThrottleLimit <Int32>]
       [-WhatIf]
       [-Confirm]
       [<CommonParameters>]

Description

The Restart-Computer cmdlet restarts the operating system on the local and remote computers.

You can use the parameters of Restart-Computer to run the restart operations as a background job, to specify the authentication levels and alternate credentials, to limit the operations that run at the same time, and to force an immediate restart.

Starting in Windows PowerShell 3.0, you can wait for the restart to complete before you run the next command, specify a waiting time-out and query interval, and wait for particular services to be available on the restarted computer. This feature makes it practical to use Restart-Computer in scripts and functions. You can also use the WSMan protocol to restart the computer, in case DCOM calls are blocked, such as by an enterprise firewall.

This cmdlet requires Windows PowerShell remoting only when you use the AsJob parameter in a command.

Examples

Example 1: Restart the local computer 

PS C:\> Restart-Computer

This command restarts the local computer.

Example 2: Restart several computers including the local computer 

PS C:\> Restart-Computer -ComputerName "Server01", "Server02", "localhost"

This command restarts two remote computers, Server01 and Server02, and the local computer, identified as localhost.

Example 3: Restart computers as a background job 

The first command uses the *AsJob* parameter to run the command as a background job. The command stores the resulting job object in the $j variable.

PS C:\> $j = Restart-Computer -ComputerName "Server01", "Server02" -AsJob



The second command uses a pipeline operator to send the job object in $j to the Receive-Job cmdlet, which gets the job results. The command stores the results in the $Results variable.

PS C:\> $Results = $j | Receive-Job



The third command displays the result stores in the $Results variable.Because *AsJob* creates the job on the local computer and automatically returns the results to the local computer, you can run **Receive-Job** as a local command.

PS C:\> $Results

These commands run a Restart-Computer command as a background job on two remote computers, and then get the results.

Example 4: Restart a remote computer 

PS C:\> Restart-Computer -ComputerName "Server01" -Impersonation Anonymous -Authentication PacketIntegrity

This command restarts the Server01 remote computer. The command uses customized impersonation and authentication settings.

Example 5: Force restart of all computers in a domain 

The first command uses the Get-Content cmdlet to get a list of computers in the domain from the Domain01.txt file. It stores the list in the $s variable.

PS C:\> $s = Get-Content Domain01.txt



The second command gets the credentials of a domain administrator and stores them in the $c variable.

PS C:\> $c = Get-Credential Domain01\Admin01



The third command restarts the computers. It uses the *ComputerName* parameter to submit the list of computers in the $s variable, the *Force* parameter to force an immediate restart, and the *Credential* parameter to submit the credentials saved in the $c variable. It also uses the *ThrottleLimit* parameter to limit the command to 10 concurrent connections.

PS C:\> Restart-Computer -ComputerName $s -Force -ThrottleLimit 10 -Credential $c

This example forces an immediate restart of all of the computers in Domain01.

Example 6: Restart a remote computer and wait 

PS C:\> Restart-Computer -ComputerName "Server01" -Wait -For PowerShell -Timeout 300 -Delay 2

This command restarts the Server01 remote computer and then waits up to 5 minutes (300 seconds) for Windows PowerShell to be available on the restarted computer before it continues.

The command uses the Wait , For , and Timeout parameters to specify the conditions of the wait. It uses the Delay parameter to reduce the interval between queries to the remote computer that determine whether it is restarted.

Example 7: Restart a computer by using WSMan 

PS C:\> Restart-Computer -ComputerName "Server01" -Protocol WSMan -WSManAuthentication Kerberos

This command restarts the Server01 remote computer by using the WSMan protocol, instead of DCOM, which is the default. It also uses Kerberos authentication to determine whether the current user has permission to restart the remote computer.

These settings are designed for enterprises in which DCOM-based restarts fail because DCOM is blocked, such as by a firewall.

Optional Parameters

-AsJob

Indicates that this cmdlet runs as a background job.

To use this parameter, the local and remote computers must be configured for remoting and, on Windows Vista and later versions of the Windows operating system, you must open Windows PowerShell by using the Run as administrator option. For more information, see about_Remote_Requirements .

When you specify the AsJob parameter, the command immediately returns an object that represents the background job. You can continue to work in the session while the job finishes. The job is created on the local computer and the results from remote computers are automatically returned to the local computer. To manage the job, use the Job cmdlets. To get the job results, use the Receive-Job cmdlet.

For more information about Windows PowerShell background jobs, see about_Jobs and about_Remote_Jobs .

Type: SwitchParameter
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-ComputerName

Specifies one or more computers. The default is the local computer.

Type the NETBIOS name, an IP address, or a fully qualified domain name of a remote computer. To specify the local computer, type the computer name, a dot (.), or localhost.

This parameter does not rely on Windows PowerShell remoting. You can use the ComputerName parameter even if your computer is not configured to run remote commands.

Type: String[]
Aliases: CN, __SERVER, Server, IPAddress
Position: 1
Default value: None
Accept pipeline input: True (ByPropertyName, ByValue)
Accept wildcard characters: False
-Confirm

Prompts you for confirmation before running the cmdlet.

Type: SwitchParameter
Aliases: cf
Position: Named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False
-Credential

Specifies a user account that has permission to perform this action. The default is the current user.

Type a user name, such as User01 or Domain01\User01, or enter a PSCredential object, such as one generated by the Get-Credential cmdlet.

Type: PSCredential
Position: 2
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-DcomAuthentication

Specifies the authentication level that is used for the WMI connection. The acceptable values for this parameter are:

  • Call. Call-level COM authentication
  • Connect. Connect-level COM authentication
  • Default. Windows Authentication
  • None. No COM authentication
  • Packet. Packet-level COM authentication
  • PacketIntegrity. Packet Integrity-level COM authentication
  • PacketPrivacy. Packet Privacy-level COM authentication
  • Unchanged. The authentication level is the same as the previous command

The default value is Packet.

For more information about the values of this parameter, see AuthenticationLevel Enumeration in the MSDN library.

This parameter was introduced in Windows PowerShell 3.0.

Type: AuthenticationLevel
Aliases: Authentication
Parameter Sets: Default, None, Connect, Call, Packet, PacketIntegrity, PacketPrivacy, Unchanged
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-Delay

Determines how often, in seconds, Windows PowerShell queries the service that is specified by the For parameter to determine whether it is available after the computer is restarted. Specify a delay between queries, in seconds. The default value is 5 seconds.

This parameter is valid only together with the Wait and For parameters.

This parameter was introduced in Windows PowerShell 3.0.

Type: Int16
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-For

Specifies the behavior of Windows PowerShell as it waits for the specified service or feature to become available after the computer restarts. This parameter is valid only with the Wait parameter.

The acceptable values for this parameter are:

  • Default. Waits for Windows PowerShell to restart.
  • PowerShell. Can run commands in a Windows PowerShell remote session on the computer.
  • WMI. Receives a reply to a Win32_ComputerSystem query for the computer.
  • WinRM. Can establish a remote session to the computer by using WS-Management.

This parameter was introduced in Windows PowerShell 3.0.

Type: WaitForServiceTypes
Parameter Sets: PowerShell, WinRM, Wmi
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-Force

Forces an immediate restart of the computers.

Type: SwitchParameter
Aliases: f
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-Impersonation

Specifies the impersonation level that this cmdlet uses to call WMI. Restart-Computer uses WMI. The acceptable values for this parameter are:

-- Default. Default impersonation.

  • Anonymous. Hides the identity of the caller.
  • Identify. Allows objects to query the credentials of the caller.
  • Impersonate. Allows objects to use the credentials of the caller.

The default value is Impersonate.

Type: ImpersonationLevel
Parameter Sets: Default, Anonymous, Identify, Impersonate, Delegate
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-Protocol

Specifies which protocol to use to restart the computers. The acceptable values for this parameter are: WSMan and DCOM. The default value is DCOM.

This parameter was introduced in Windows PowerShell 3.0.

Type: String
Parameter Sets: DCOM, WSMan
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-ThrottleLimit

Specifies the maximum number of concurrent connections that can be established to run this command. If you omit this parameter or enter a value of 0, the default value, 32, is used.

The throttle limit applies only to the current command, not to the session or to the computer.

Type: Int32
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-Timeout

Specifies the duration of the wait, in seconds. When the time-out elapses, Restart-Computer returns the command prompt, even if the computers are not restarted. The default value, -1, represents an indefinite time-out.

The Timeout parameter is valid only with the Wait parameter.

This parameter was introduced in Windows PowerShell 3.0.

Type: Int32
Aliases: TimeoutSec
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-Wait

Indicates that this cmdlet suppresses the Windows PowerShell prompt and blocks the pipeline until all of the computers have restarted. You can use this parameter in a script to restart computers and then continue to process when the restart is finished.

By default, Wait waits indefinitely for the computers to restart, but you can use Timeout to adjust the timing and the For and Delay parameters to wait for particular services to be available on the restarted computers.

The Wait parameter is not valid when you are restarting the local computer. If the value of the ComputerName parameter contains the names of remote computers and the local computer, Restart-Computer generates a non-terminating error for Wait on the local computer, but it waits for the remote computers to restart.

This parameter was introduced in Windows PowerShell 3.0.

Type: SwitchParameter
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False
-WhatIf

Shows what would happen if the cmdlet runs. The cmdlet is not run.

Type: SwitchParameter
Aliases: wi
Position: Named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False
-WsmanAuthentication

Specifies the mechanism that is used to authenticate the user credentials when you use the WSMan protocol.

The acceptable values for this parameter are: Basic, CredSSP, Default, Digest, Kerberos, and Negotiate. The default value is Default. For more information about the values of this parameter, see AuthenticationMechanism Enumeration in the MSDN library.

Caution: Credential Security Service Provider (CredSSP) authentication, in which the user credentials are passed to a remote computer to be authenticated, is designed for commands that require authentication on more than one resource, such as accessing a remote network share. This mechanism increases the security risk of the remote operation. If the remote computer is compromised, the credentials that are passed to it can be used to control the network session.

This parameter was introduced in Windows PowerShell 3.0.

Type: String
Parameter Sets: Default, Basic, Negotiate, CredSSP, Digest, Kerberos
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

Inputs

System.String

You can pipe computer names to this cmdlet..

In Windows PowerShell 2.0, the ComputerName parameter takes input from the pipeline only by property name. In Windows PowerShell 3.0, the ComputerName parameter takes input from the pipeline by value.

Outputs

None, System.Management.Automation.RemotingJob

This cmdlet returns a job object, if you specify the AsJob parameter. Otherwise, it does not generate any output.

Notes

  • This cmdlet uses the Win32Shutdown method of the WMI WIN32_OperatingSystem class.
  • In Windows PowerShell 2.0, AsJob does not work reliably when you are restarting/stopping remote computers. In Windows PowerShell 3.0, the implementation is changed to resolve this problem.