I am looking for a command that will accept (as input) multiple lines of text, each line containing a single integer, and output the sum of these integers.

As a bit of background, I have a log file which includes timing measurements. Through grepping for the relevant lines and a bit of sed reformatting I can list all of the timings in that file. I would like to work out the total. I can pipe this intermediate output to any command in order to do the final sum. I have always used expr in the past, but unless it runs in RPN mode I do not think it is going to cope with this (and even then it would be tricky).

How can I get the summation of integers?