Simple node.js script that takes input, splits it into lines, and does something with it (removes/counts duplicates, in this case).

gistfile1.js

process.stdin.resume();
process.stdin.setEncoding('utf8');

var lineCounts = {}; 
var previousFragment = '';
process.stdin.on('data', function (chunk) {
	var lines = chunk.split( '\n' );
	lines[0] = previousFragment + lines[0];
	previousFragment = lines.pop();
	lines.forEach( function( line ) {
		if( lineCounts.hasOwnProperty( line ))
			lineCounts[ line ] ++;
		else
		{
			lineCounts[ line ] = 1;
		}
	});
});
process.stdin.on( 'close', function() {
	var total = 0;
	var unique = 0;
	for( var k in lineCounts )
	{
		if( lineCounts.hasOwnProperty( k ))
		{
			total += lineCounts[ k ];
			unique ++;
			console.log( k );
		}
	}

/*	console.log( 'Total lines: ' + total );
	console.log( 'Total unique lines: ' + unique );
	console.log( 'Number of occurances by line: ' );
	console.log( lineCounts );*/
});