functions/Set-DbaAgentJobCategory.ps1

function Set-DbaAgentJobCategory {
<#
    .SYNOPSIS
        Set-DbaAgentJobCategory changes a job category.
 
    .DESCRIPTION
        Set-DbaAgentJobCategory makes it possible to change a job category.
 
    .PARAMETER SqlInstance
        The target SQL Server instance or instances. You must have sysadmin access and server version must be SQL Server version 2000 or greater.
 
    .PARAMETER SqlCredential
        Login to the target instance using alternative credentials. Windows and SQL Authentication supported. Accepts credential objects (Get-Credential)
 
    .PARAMETER Category
        The name of the category
 
    .PARAMETER NewName
        New name of the job category
 
    .PARAMETER Force
        The force parameter will ignore some errors in the parameters and assume defaults.
 
    .PARAMETER WhatIf
        Shows what would happen if the command were to run. No actions are actually performed.
 
    .PARAMETER Confirm
        Prompts you for confirmation before executing any changing operations within the command.
 
    .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, Job, JobCategory
        Author: Sander Stad (@sqlstad), sqlstad.nl
 
        Website: https://dbatools.io
        Copyright: (c) 2018 by dbatools, licensed under MIT
        License: MIT https://opensource.org/licenses/MIT
 
    .LINK
        https://dbatools.io/Set-DbaAgentJobCategory
 
    .EXAMPLE
        PS C:\> New-DbaAgentJobCategory -SqlInstance sql1 -Category 'Category 1' -NewName 'Category 2'
 
        Change the name of the category from 'Category 1' to 'Category 2'.
 
    .EXAMPLE
        PS C:\> Set-DbaAgentJobCategory -SqlInstance sql1, sql2 -Category Category1, Category2 -NewName cat1, cat2
 
        Rename multiple jobs in one go on multiple servers.
 
#>

    [CmdletBinding(SupportsShouldProcess = $true, ConfirmImpact = "Low")]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [Parameter(Mandatory = $false)]
        [ValidateNotNullOrEmpty()]
        [string[]]$Category,
        [string[]]$NewName,
        [switch]$Force,
        [Alias('Silent')]
        [switch]$EnableException
    )

    begin {
        # Create array list to hold the results
        $collection = New-Object System.Collections.ArrayList

        # Check if multiple categories are being changed
        if ($Category.Count -gt 1 -and $NewName.Count -eq 1) {
            Stop-Function -Message "You cannot rename multiple jobs to the same name" -Target $instance
        }
    }

    process {

        foreach ($instance in $sqlinstance) {
            # Try connecting to the instance
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }

            # Loop through each of the categories
            foreach ($cat in $Category) {
                # Check if the category exists
                if ($cat -notin $server.JobServer.JobCategories.Name) {
                    Stop-Function -Message "Job category $cat doesn't exist on $instance" -Target $instance -Continue
                }

                # Check if the category already exists
                if ($NewName -and ($NewName -in $server.JobServer.JobCategories.Name)) {
                    Stop-Function -Message "Job category $NewName already exists on $instance" -Target $instance -Continue
                }

                if ($PSCmdlet.ShouldProcess($instance, "Changing the job category $Category")) {
                    try {
                        # Get the job category object
                        $currentCategory = $server.JobServer.JobCategories[$cat]

                        Write-Message -Message "Changing job category $cat" -Level Verbose

                        # Get and set the original and new values
                        $originalCategoryName = $currentCategory.Name
                        $newCategoryName = $null

                        # Check if the job category needs to be renamed
                        if ($NewName) {
                            $currentCategory.Rename($NewName[$Category.IndexOf($cat)])
                            $newCategoryName = $currentCategory.Name
                        }

                        # Set up the custom object
                        $null = $collection.Add([PSCustomObject]@{
                                ComputerName    = $server.ComputerName
                                InstanceName    = $server.ServiceName
                                SqlInstance     = $server.DomainInstanceName
                                CategoryName    = $originalCategoryName
                                NewCategoryName = $newCategoryName
                            })

                    }
                    catch {
                        Stop-Function -Message "Something went wrong changing the job category $cat on $instance" -Target $cat -Continue -ErrorRecord $_
                    }

                } # if should process

            } # for each category

        } # foreach instance

        # Return result
        return $collection

    } # end process

    end {
        if (Test-FunctionInterrupt) { return }
        Write-Message -Message "Finished changing job category." -Level Verbose
    }

}