PowerShell script to Check-In items in a list or library

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

$WebURL= "http://sp2013"
$LibraryName = "Documents"

#Get Site and Library

$Web = Get-SPWeb $WebURL
$DocLib = $Web.Lists.TryGetList($LibraryName)

#Get all Checked out files

$CheckedOutFiles = $DocLib.Items | Where-Object { $_.File.CheckOutStatus -ne "None"}

#Check in All Checked out Files in the library

ForEach($item in $CheckedOutFiles)
    {
        #If you want to update fields
        #$item["Field"] = "value"
        #$item.SystemUpdate()
 
        #check in file programmatically    
        #$item.TakeoverCheckout()
        $DocLib.GetItemById($item.Id).file.CheckIn("")
        write-host "File:'$($item.Name)' has been checked in!"
        }