#!/bin/bash

# order by
by="swap"

# reverse sort
rev="r"

if [ ! -z "$1" ]; then
	case "$1" in
		-s|--swap|swap)
			by="swap"
			shift
			;;
		-m|--memory|mem|memory)
			by="memory"
			shift
			;;
		-n|--name|-p|--process|--program|name|proc|process)
			by="name"
			rev=""
			shift
			;;
		-h|--help|help)	
			echo "Statistics about all running processes."
			echo "Usage: $0 [OPTION]"
			echo "	swap	sort by swap usage (default)"
			echo "	memory	sort by memory usage"
			echo "	name	sort by process name"
			echo "	help	print this help message"
			exit 0 
			;;
		*)
			echo "Unrecognized option \"$1\"" >&2
			echo "Try -h instead."
			exit 1
	esac
fi

echo "Check memory and swap usage for all programs sorted by $by."
echo ""

# loop over all running programs
for CMD in $(top -bn1 | tail -n +8 | grep -v $(basename "$0") | awk '{print $12}' | sort | uniq)
do
	swap_count=0
	mem_count=0

	# loop over all pids and check for 'VmSize' and 'VmSwap' state in /proc/$PID/status
	for tmp in $( for PID in $(pgrep $CMD 2>/dev/null); do grep -E 'Vm(Size|Swap)' /proc/$PID/status 2>/dev/null | paste - - | awk '{print $2 "|" $5}'; done )
	do 
		mem_count=$(($mem_count+$(echo $tmp | cut -d\| -f1)))
		swap_count=$(($swap_count+$(echo $tmp | cut -d\| -f2)))
	done

	# programs swap use is not null
	if [ $swap_count -gt 0 ]
	then
		case "$by" in
			swap)
				echo "$swap_count kB (Swap): $CMD $mem_count kB (Memory)"
				;;
			memory)
				echo "$mem_count kB (Memory): $CMD $swap_count kB (Swap)"
				;;
			name)
				echo "$CMD: $mem_count kB (Memory) $swap_count kB (Swap)"
				;;
		esac
	fi

# sort by swap usage
done | sort -k1 -t\  -h${rev} | column -t