store-vs-publish

class Util {
    static def whois(def number) {
        def subdir = ['one', 'two', 'three']
        return subdir[number-1]
    }
}

ch = Channel.from(1, 2, 3)

process parallel {
    echo true
    publishDir "$storage/${Util.whois(no)}", mode: 'copy'

    input:
    val(no) from ch

    output:
    file('*.txt') into parallel_out

    script:
"""
echo "A_${no}" > A_${no}.txt
echo "B_${no}" > B_${no}.txt
"""
}

process join {
    echo true
    publishDir "$storage"

    input:
    file('*') from parallel_out.flatten().toList()

    output:
    file('*.txt') into join_out

script:
"""
cat A_1.txt A_2.txt A_3.txt > A_join.txt
cat B_1.txt B_2.txt B_3.txt > B_join.txt
"""
}