How to activate a set of standard list of features in all site collections for a web application using Powershell in SharePoint 2010

Problem: 

The department has a site collection that is heavily used and is a key site collection.The business would like to standardise site collection features across the board. 
How to activate a standard list of features in all site collections for a web application using powershell script for SharePoint.

Solution:
Note: # is a comment in powershell

Contents of  ManualListofFeaturesInEDSite.txt - This contains all the features that need to be activated. If you do not wish to read from a text file and use a reference site then just use 

$allSiteColFeature = Get-SPFeature -site "http://muwebapp/sites/nintex" | Select displayname, id 
NintexWorkflow
NintexWorkflowWebParts
NintexWorkflowInfoPath
NintexWorkflowEnterpriseWebParts
NintexWorkflowContentTypeUpgrade
OfficeWebApps
OpenInClient
ReviewPublishingSPD1033
ReportServer
Reporting
PublishingSite
BaseSite
InPlaceRecords
LocationBasedPolicy
WAReports
DocumentSet
DocId
Workflows
LocationBasedPolicy
ViewFormPagesLockDown

 ***** Script begins here ******
  Add-PSSnapin microsoft.sharepoint.powershell -ErrorAction SilentlyContinue

$ErrorActionPreference="SilentlyContinue"
Stop-Transcript | out-null
$ErrorActionPreference = "Continue"
Start-Transcript -path C:\Admin\SiteFeaturesoutput.txt -append

 $webs =  get-spsite -webapplication "http://mywebapp" -Limit All
 # Returns a detailed list of features, hence not being used
 #$allSiteColFeature = Get-SPFeature -site "http://muwebapp/sites/nintex" | Select displayname, id
 
 $fileContent = Get-Content "C:\drive\PROJECTS\DEVELOPMEN\ManualListofFeaturesInEDSite.txt"
 
#$oneweb = "http://mywebapp/sites/nintex"
   
    Foreach ($oneweb in $webs)
    {
        Foreach ($featureId in $fileContent)
        {
            #$siteFeature = get-spfeature -site $oneweb | Where {$_.id -eq $featureId.id}
            $siteFeature = get-spfeature -site $oneweb | Where {$_.displayname -eq $featureId.displayname}
           
            if ($siteFeature -eq $null)
            {
              Write-Host "Activating Site level Features at $oneweb FeatureID: $featureid" -foregroundcolor Yellow
               Enable-SPFeature $featureId -URL $oneweb.URL -Confirm:$False
              #Disable-SPFeature $featureId -URL $oneweb.URL -Confirm:$False
              #Enable-SPFeature $featureId -URL $oneweb -Confirm:$False
            }
            else
            {
              Write-Host "Feature $feature is already activated on $oneweb" -foregroundcolor green
            }
        }
    }

Stop-Transcript


****** End of Script ******