import "merge.wdl" as sub workflow merge_and_cut { Array[Array[Array[File]]] smallfiles = [] scatter(smallfiles_ in smallfiles) { call sub.merge {input: smallfiles = smallfiles_} } call cut {input: files = merge.merged} output { File merged_and_cut = cut.cut1 } } task cut { Array[File] files = [] command { cut -c1 ${sep=" " files} > cut1 } output { File cut1 = "cut1" } runtime { docker: "ubuntu:20.04" } }