Unexpected Serial.read

/*
Teaching my self programing for the Arduino I have been able to work through most
problems that I have encountered but I have now hit a brick wall,
to explain my problem I have writen and tested this piece of code that I would expect
to print out an indication of what is entered into the serial monitor

I have tried this on several Arduinos, including an official uno
board, a cheap import with 340 and an evan cheaper pro mini.
typing in '1' the monitor provides 49 (this I understand) but it prints out
two more lines which regadless of the input are always 13, and then 10

on more complex code it preforms as expected but seems to repeat the result 
three times on the monitor
I have also tried placing delays of up to 1000 but still get everyting in triplicate

*/
int dataInput;  //the data I want to use

void setup()
{
 Serial.begin(9600); 
}

  void loop()
{
 if(Serial.available())  //wait for an input
{
 dataInput = Serial.read(); //read and remember the input

 Serial.println(dataInput); //print the input out on the screen
} 
}/code]

Also I am using a mac OS X Yosemite 10.10.3

Println adds a carriage return (ASCII code 13) and a line feed (ASCII code 10) to the end of the line printed.

access2it: typing in '1' the monitor provides 49 (this I understand) but it prints out two more lines which regadless of the input are always 13, and then 10

In the little menu at the bottom of Serial Monitor change line ending from "Both NL & CR" to "No line ending". Line endings are often use in terminal emulators to let the receiving device know that the Return/Enter key was pressed.