If you want to hide few sharepoint list fields in Display Form .Here is the Powershell scripts for you
$web = Get-SPWeb "http://mysite"
$list = $web.Lists["Your List"]
$f = $list.Fields.GetFieldByInternalName("FieldName")
$f.ShowInDisplayForm = $false
$f.Update()
To hide a sharepoint List Field in Edit Form
$web = Get-SPWeb "http://mysite"
$list = $web.Lists["Custom List"]
$f = $list.Fields.GetFieldByInternalName("FieldName")
$f.ShowInEditForm = $false
$f.Update()
To hide a sharepoint List Field in NewForm
$web = Get-SPWeb "http://mysite"
$list = $web.Lists["Custom List"]
$f = $list.Fields.GetFieldByInternalName("FieldName")
$f.ShowInNewForm = $false
$f.Update()
Happy SharePointing :-)