missing_opt.conf

[fstab_missing_opt]
path = /files/etc/fstab/*[label()=~regexp('[0-9]+') and count(opt[.='foo'])=0]
method = label
type = multiple
sep = ,

missing_opt.pp

define fstab_opt (
  $entry,
  $value,
) {
  augeas { "Set fstab opt for ${entry}":
     context => "./${entry}",
     changes => "set opt[last()+1] ${value}",
  }
}


fstab_missing_opt { slit($::fstab_missing_opt, ','):
  value => 'foo',
}