params.str = "Hello, world!"

process split {
	publishDir "results/lower"

	input:
	val x

	output:
	path 'chunk_*'

	script:
	"""
	printf '${x}' | split -b 6 - chunk_
	"""
}

process to_upper {
	tag "$y"

	input:
	path y

	output:
	path 'upper_*'

	script:
	"""
		cat $y | tr '[a-z]' '[A-Z]' > upper_${y}
	"""
}

workflow {
	main:
	ch_str = channel.of(params.str)
	ch_chunks = split(ch_str)
	ch_upper = to_upper(ch_chunks.flatten())

	publish:
	lower = ch_chunks.flatten()
	upper = ch_upper
}

output {
	lower {
		path 'lower'
	}

	upper {
		path 'upper'
	}
}