1 2v=XaaaXbbbX 3[ "${v\ 4#\ 5*\ 6a}.${v\ 7#\ 8#\ 9*\ 10a}.${v\ 11%\ 12b\ 13*}.${v\ 14%\ 15%\ 16b\ 17*}" = aaXbbbX.XbbbX.XaaaXbb.XaaaX ] 18