#!/usr/bin/env nextflow params.str = 'Hello world!' process splitLetters { output: file 'chunk_*' into letters """ printf '${params.str}' | split -b 6 - chunk_ """ } process convertToUpper { input: file x from letters.flatten() output: stdout result """ cat $x | tr '[a-z]' '[A-Z]' """ } result.view { it.trim() }