After looking through the responses I think I found a quicker way (simpler). Using the data I managed to get it to work with:
setwd("~/Documents/Random/abs") # data here
a = read_bulk(directory = ".") # read in as i did
df = unstack(a) # line i was looking for
dat = as.matrix(df) # to matrix
matplot(dat, lty = 1, type = 'l', lwd = 1, xlab = "Energy (keV)", ylab = "Counts") # plot
