ref: 279f78a86cbff3f526fe1a1debd4d4f5766f96b0 dir: /test/t.array1/
{for(i=1; i<=NF; i++) { if (x[$i] == "") y[++n] = $i x[$i]++ } } END { for (i=0; i<n; i++) print (y[i], x[y[i]]) }