I'm using streamline to profile an application but I'm interested only in the grand finale total sum of a particular counter. Is there this functionality in streamline or do I've to process the whole streamline report output and sum up the values of the time series?
Yes - there's a light blue bar at the top of the timeline, which by default starts over on the left hand side. You can use this to select a range, where it will give you the sum over that range (or average, depending on the counter being collected).
In your case, if you drag the bar to extend over the full report, it will tell you the total. Here's a sample screenshot, which shows everything to the left of the white line being summed or averaged. For reference, I've hovered the mouse over a point a little further along so you can see the instantaneous value:
Hope this helps,
that was exactly what I was looking for. One follow up question is: Is there a way to collect this "summary information" from command line?
It's not directly possible, though you could just output everything and then sum the counter you're interested in with a script (or other method). Here's the info on using Streamline from the command line if it helps:
ARM DS-5 Using ARM Streamline : Chapter 15 Using Streamline on the Command Line