combine.nf

Channel
  .from ( 'a.vcf', 'b.vcf', 'c.vcf')
  .into { vcf_files1; vcf_files2 }


process clinvar { 
  input:
  file(vcf) from vcf_files1

  output:
  file 'x.txt' into vcf_res1

   """
   touch x.txt
   """ 
}

process snpeff {
  input:
  file(vcf) from vcf_files2

  output:
  file 'y.txt' into vcf_res2

  """
  touch 'y.txt' 
  """
}

process combine{
  echo true
  input: 
  file(vcf1) from vcf_res1
  file(vcf2) from vcf_res2

  """
  echo combine $vcf1 $vcf2
  """
}