About Scheduled Jobs
Short description
Describes scheduled jobs and explains how to use and manage scheduled jobs in PowerShell and in Task Scheduler.
Long description
PowerShell scheduled jobs are a useful hybrid of PowerShell background jobs and Task Scheduler tasks.
Like PowerShell background jobs, scheduled jobs run asynchronously in the
background. Instances of scheduled jobs that have run can be managed by using
the job cmdlets, such as Start-Job, Get-Job, Stop-Job, and Receive-Job.
Like Task Scheduler tasks, scheduled jobs are saved to disk. You can view and manage the jobs in Task Scheduler, enable and disable them as needed, run them or use them as templates, establish a one-time or recurring schedules for starting the jobs, or set conditions under which the jobs start.
In addition, the results of scheduled job instances are saved to disk in an easily accessible format, providing a running log of job output. Scheduled jobs come with a customized set of cmdlets for managing them. The cmdlets let you create, edit, manage, disable, and re-enable scheduled jobs, job triggers and job options.
This comprehensive and flexible set of tools make scheduled jobs an essential component of many professional PowerShell IT solutions.
The scheduled job cmdlets are included in the PSScheduledJob module that is installed with PowerShell. This module was introduced in PowerShell 3.0 and works in PowerShell 3.0 and later versions of PowerShell. For more information about the cmdlets contained in the PSScheduledJob module.
For more information about PowerShell background jobs, see about_Jobs.
For more information about Task Scheduler, see Task Scheduler.
Note
You can view and manage PowerShell scheduled jobs in Task Scheduler. The PowerShell jobs and scheduled job cmdlets work only on scheduled jobs that are created in PowerShell.
Quick start
This example creates a scheduled job that starts every day at 3:00 AM and runs
the Get-Process cmdlet. The job starts even if the computer is running on
batteries.
$trigger = New-JobTrigger -Daily -At 3AM
$options = New-ScheduledJobOption -StartIfOnBattery
Register-ScheduledJob -Name ProcessJob -ScriptBlock {Get-Process} `
-Trigger $trigger -ScheduledJobOption $options
The Get-ScheduledJob cmdlet gets the scheduled jobs on the local computer.
Get-ScheduledJob
Id Name Triggers Command Enabled
-- ---- -------- ------- -------
7 ProcessJob {1} Get-Process True
Get-JobTrigger gets the job triggers of ProcessJob. The input parameters
specify the scheduled job, not the trigger, because triggers are saved in a
scheduled job.
Get-JobTrigger -Name ProcessJob
Id Frequency Time DaysOfWeek Enabled
-- --------- ---- ---------- -------
1 Daily 11/5/2011 3:00:00 AM True
This example uses the ContinueIfGoingOnBattery parameter of the
Set-ScheduledJob cmdlet to change the StopIfGoingOnBatteries property of
ProcessJob to False.
Get-ScheduledJob -Name ProcessJob | Set-ScheduledJobOption `
-ContinueIfGoingOnBattery -Passthru
StartIfOnBatteries : True
StopIfGoingOnBatteries : False
WakeToRun : True
StartIfNotIdle : True
StopIfGoingOffIdle : False
RestartOnIdleResume : False
IdleDuration : 00:10:00
IdleTimeout : 01:00:00
ShowInTaskScheduler : True
RunElevated : False
RunWithoutNetwork : True
DoNotAllowDemandStart : False
MultipleInstancePolicy : IgnoreNew
JobDefinition : Microsoft.PowerShell.ScheduledJob.ScheduledJobDefinition
The Get-ScheduledJob cmdlet gets the ProcessJob scheduled job.
Get-ScheduledJob ProcessJob
Id Name Triggers Command Enabled
-- ---- -------- ------- -------
7 ProcessJob {1} Get-Process True
The Get-Job cmdlet gets all instances of the ProcessJob scheduled job
that have run thus far. The Get-Job cmdlet gets scheduled jobs only when the
PSScheduledJob module is imported into the current session.
Tip
Notice that you use the scheduled job cmdlets to manage scheduled jobs, but you use the job cmdlets to manage instances of scheduled jobs.
Get-Job -Name ProcessJob
Id Name PSJobTypeName State HasMoreData Location Command
-- ---- ------------ ----- ----------- -------- -------
45 ProcessJob PSScheduledJob Completed True localhost Get-Process
46 ProcessJob PSScheduledJob Completed True localhost Get-Process
47 ProcessJob PSScheduledJob Completed True localhost Get-Process
48 ProcessJob PSScheduledJob Completed True localhost Get-Process
49 ProcessJob PSScheduledJob Completed True localhost Get-Process
50 ProcessJob PSScheduledJob Completed True localhost Get-Process
51 ProcessJob PSScheduledJob Completed True localhost Get-Process
The Receive-Job cmdlet gets the results of the most recent instance of the
ProcessJob scheduled job (ID = 51).
Receive-Job -ID 51
Even though the Receive-Job command did not include the Keep parameter,
the results of the job are saved on disk until you delete them or the maximum
number of results are exceeded.
The job results are no longer available in this session, but if you start a new session or open a new PowerShell window, the results of the job are available again.
The following command uses the DefinitionName parameter of the Start-Job
cmdlet to start the ProcessJob scheduled job.
Jobs that are started by using the Start-Job cmdlet are standard PowerShell
background jobs, not instances of the scheduled job. Like all background jobs,
these jobs start immediately, they aren't subject to job options or affected by
job triggers, and their output is not saved in the output directory of the
scheduled job directory.
Start-Job -DefinitionName ProcessJob
The Unregister-ScheduledJob cmdlet deletes the ProcessJob scheduled job
and all saved results of its job instances.
Unregister-ScheduledJob ProcessJob
Scheduled jobs concepts
A scheduled job runs commands or a script. A scheduled job can include job triggers that start the job and job options that set conditions for running the job.
A job trigger starts a scheduled job automatically. A job trigger can include a one-time or recurring schedule or specify an event, such as when a user logs on or Windows starts. A scheduled job can have one or more job triggers, and you can create, add, enable, disable, and get job triggers.
Job triggers are optional. You can start scheduled jobs immediately by using
the Start-Job cmdlet, or by adding the RunNow parameter to your
Register-ScheduledJob command.
Job options set the conditions for running a scheduled job. Every scheduled job has one job options object. You can create and edit job options objects and add them to one or more scheduled jobs.
Each time a scheduled job starts, a job instance is created. Use the PowerShell job cmdlets to view and manage the job instance.
Scheduled jobs are saved to disk and use the cmdlet verb, Register, instead
of New. The XML files are located on the local computer in the directory
$home\AppData\Local\Microsoft\Windows\PowerShell\ScheduledJobs.
PowerShell creates a directory for each scheduled job and saves the job commands, job triggers, job options and job results in the scheduled job directory. Job triggers and job options aren't saved to disk independently. They are saved in the scheduled job XML of each scheduled job with which they are associated.
Scheduled jobs, job triggers, and job options appear in PowerShell as objects. The objects are interlinked, which makes them easy to discover and use in commands and scripts.
Scheduled jobs appear as ScheduledJobDefinition objects. The ScheduledJobDefinition object has a JobTriggers property that contains the job triggers of the scheduled job and an Options property that contains the job options. The ScheduledJobTriggers and ScheduledJobOptions objects that represent job triggers and job options, respectively, each have a JobDefinition property that contains the scheduled job with which they are associated. This recursive interconnection makes it easy to find the triggers and options of a scheduled job and to find, script, and display the scheduled job to which any job trigger or job option is associated.