library(data.table) library(parallel) files <- commandArgs(trailingOnly = TRUE) nlines <- 731759 reader <- function(file) { fread(file, header = TRUE, colClasses = rep("double", 16)) } cl <- makeForkCluster() files.content <- parSapplyLB(cl, files, reader) vfiles.content <- unlist(files.content, recursive = FALSE) dim(vfiles.content) <- c(nlines, 16, 6)