ref: 3ddd7b252f8d0dacee2a7556e5ffb0d54bcf4f58 dir: /testdir/t.aeiouy/
/^[^aeiouy]*a[^aeiouy]*e[^aeiouy]*i[^aeiouy]*o[^aeiouy]*u[^aeiouy]*y[^aeiouy]*$/