Two columns A and B: Column A have repeated ids and column B has different values for each corresponding  repeated value. I would like to read every uniq value from Column A with only the first hit from column BFile_B.txtA 1A 2B 3B 2B 4C 1C 5D 4D 3E 2Output:A 1B 3C 1D 4E 2
grep first column uniq values
awk;grep