bash-completion/swapoff

_swapoff_module()
{
	local cur prev OPTS
	COMPREPLY=()
	cur="${COMP_WORDS[COMP_CWORD]}"
	prev="${COMP_WORDS[COMP_CWORD-1]}"
	case $prev in
		'-a'|'--all')
			return 0
			;;
		'-U'|'UUID=')
			# only works for block devices, i.e., not for swap files.
			local SWAPS
			SWAPS="$(swapon --show=TYPE,NAME --raw --noheading | \
				awk '$1 !~ /file/ { print $2 }')"
			[ -z "$SWAPS" ] && return 0
			local UUIDS
			UUIDS="$(lsblk -nrp -o UUID "$SWAPS")"
			COMPREPLY=( $(compgen -W "$UUIDS" -- $cur) )
			return 0
			;;
		'-L'|'LABEL=')
			# only works for block devices, i.e., not for swap files.
			local SWAPS
			SWAPS="$(swapon --show=TYPE,NAME --raw --noheading | \
				awk '$1 !~ /file/ { print $2 }')"
			[ -z "$SWAPS" ] && return 0
			local LABELS
			LABELS="$(lsblk -nrp -o LABEL "$SWAPS")"
			COMPREPLY=( $(compgen -W "$LABELS" -- $cur) )
			return 0
			;;
		'-h'|'--help'|'-V'|'--version')
			return 0
			;;
	esac
	case $cur in
		-*)
			OPTS="-L
				-U
				--all
				--verbose
				--help
				--version"
			COMPREPLY=( $(compgen -W "${OPTS[*]}" -- $cur) )
			return 0
			;;
	esac
	local DEVS
	DEVS="$(swapon --show=NAME --raw --noheading)"
	COMPREPLY=( $(compgen -W "$DEVS" -- $cur) )
	return 0
}
complete -F _swapoff_module swapoff