Demo of taking input file with exec block

execFile.nf

#!/usr/bin/env nextflow

process foo {
  output:
  file "out.txt" into fooFiles
  
  shell:
  '''
  echo "hi" > "out.txt";
  '''
}

process bar {
  input:
  file fooFile from fooFiles

  exec:
  println(fooFile.toFile().exists()); # prints false

}