# cat /tmp/test.R x <- 1:10 y <- 1:20 plot(x, y) # R --quiet > source("/tmp/test.R") Error in xy.coords(x, y, xlabel, ylabel, log) : 'x' and 'y

# cat /tmp/test.R x <- 1:10 y <- 1:20 plot(x, y) # R --quiet > source("/tmp/test.R") Error in xy.coords(x, y, xlabel, ylabel, log) : 'x' and 'y' lengths differ > traceback() 8: stop("'x' and 'y' lengths differ") 7: xy.coords(x, y, xlabel, ylabel, log) 6: plot.default(x, y) 5: plot(x, y) at test.R#3 4: eval(ei, envir) 3: eval(ei, envir) 2: withVisible(eval(ei, envir)) 1: source("/tmp/test.R") If you mean the lines in the packages you used, I think you'll see the lines if you build them with keep.source=TRUE