functions/Get-DbaAgentSchedule.ps1

function Get-DbaAgentSchedule {
    <#
        .SYNOPSIS
            Returns all SQL Agent Shared Schedules on a SQL Server Agent.
 
        .DESCRIPTION
            This function returns SQL Agent Shared Schedules.
 
        .PARAMETER SqlInstance
            SqlInstance name or SMO object representing the SQL Server to connect to.
            This can be a collection and receive pipeline input.
 
        .PARAMETER SqlCredential
            PSCredential object to connect as. If not specified, current Windows login will be used.
 
        .PARAMETER EnableException
            By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
            This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
            Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
             
        .NOTES
            Tags: Agent, Schedule
            Author: Chris McKeown (@devopsfu), http://www.devopsfu.com
 
            Website: https://dbatools.io
            Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
            License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
        .LINK
            https://dbatools.io/Get-DbaAgentSchedule
 
        .EXAMPLE
            Get-DbaAgentSchedule -SqlInstance localhost
 
            Returns all SQL Agent Shared Schedules on the local default SQL Server instance
 
        .EXAMPLE
            Get-DbaAgentSchedule -SqlInstance localhost, sql2016
 
            Returns all SQL Agent Shared Schedules for the local and sql2016 SQL Server instances
    #>

    [CmdletBinding()]
    param (
        [parameter(Position = 0, Mandatory = $true, ValueFromPipeline = $True)]
        [Alias("ServerInstance", "Instance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [switch][Alias('Silent')]$EnableException
    )

    process {
        foreach ($instance in $SqlInstance) {
            Write-Message -Level Verbose -Message "Attempting to connect to $instance"
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }

            if ($server.Edition -like 'Express*') {
                Stop-Function -Message "$($server.Edition) does not support SQL Server Agent. Skipping $server." -Continue
            }

            $defaults = "ComputerName", "InstanceName", "SqlInstance", "Name as ScheduleName", "ActiveEndDate", "ActiveEndTimeOfDay", "ActiveStartDate", "ActiveStartTimeOfDay", "DateCreated", "FrequencyInterval", "FrequencyRecurrenceFactor", "FrequencyRelativeIntervals", "FrequencySubDayInterval", "FrequencySubDayTypes", "FrequencyTypes", "IsEnabled", "JobCount"

            foreach ($schedule in $server.JobServer.SharedSchedules) {
                Add-Member -Force -InputObject $schedule -MemberType NoteProperty ComputerName -value $server.NetName
                Add-Member -Force -InputObject $schedule -MemberType NoteProperty InstanceName -value $server.ServiceName
                Add-Member -Force -InputObject $schedule -MemberType NoteProperty SqlInstance -value $server.DomainInstanceName

                Select-DefaultView -InputObject $schedule -Property $defaults
            }
        }
    }
}