distinct rows with column 1 and 2.

distinct.sh

#!/bin/bash

rm -f $2
echo "start $(date)"
cat $1 | while read line
do
  echo "${line}" | awk -F, -v prev_id="${prev_id}" -v prev_date="${prev_date}" '
    {if ($1 != prev_id || $2 != prev_date) print $0}
  ' >> $2
  prev_id=`echo "${line}" | awk -F, '{print $1}'`
  prev_date=`echo  "${line}" | awk -F, '{print $2}'`
done
echo "end $(date)"

distinct_hs.sh

#!/bin/bash

rm -f $2
prev_id="init"
prev_date="init"

echo "start $(date)"

cat $1 | while read line
do
  current_id=`echo "${line}" | awk -F, '{print $1}'`
  current_date=`echo  "${line}" | awk -F, '{print $2}'`

  if [ "${current_date}" != "${prev_date}" ]; then
    echo "${line}" >> $2
  elif [ "${current_id}" != "${prev_id}" ]; then
    echo "${line}" >> $2
  fi

  prev_id="${current_id}"
  prev_date="${current_date}"
done

echo "end $(date)"

FilePrinter.java

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class FilePrinter {
	public void distinctLine(String inputPath, String outputPath) {
		String delimiter = ",";

		// set encoding for multi-byte language
		try (FileInputStream fi = new FileInputStream(inputPath);
				InputStreamReader ir = new InputStreamReader(fi, "UTF-8");
				BufferedReader br = new BufferedReader(ir);
				FileOutputStream fo = new FileOutputStream(outputPath);
				OutputStreamWriter ow = new OutputStreamWriter(fo, "UTF-8");
				BufferedWriter bw = new BufferedWriter(ow)) {
			String line;
			String prev_id = "";
			String prev_date = "";

			while ((line = br.readLine()) != null) {
				String[] eachColumnValue = line.split(delimiter, -1);
				String current_id = "";
				String current_date = "";

				current_id = eachColumnValue[0];
				current_date = eachColumnValue[1];

				if (!current_date.equals(prev_date) || !current_id.equals(prev_id)) {
					bw.write(line + "\n");
				}

				prev_id = current_id;
				prev_date = current_date;
			}

			// close one by one.
			// this try braket is written with try-catch-resources style, so you
			// do not need to write close() in catch/finally braket
			bw.close();
			ow.close();
			fo.close();
			br.close();
			ir.close();
			fi.close();

		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}