if test -f cleaned_input.txt; then INPUT=$(cat cleaned_input.txt) else INPUT="3 4\n4 3\n2 5\n1 3\n3 9\n3 3" fi L1=$(printf "%b" "$INPUT" | awk '{print $1}' | sort -n) L2=$(printf "%b" "$INPUT" | awk '{print $2}' | sort -n) L1_ARRAY=($L1) L2_ARRAY=($L2) SUM=0 for i in ${!L1_ARRAY[@]}; do DIFF=$(( ${L1_ARRAY[$i]} - ${L2_ARRAY[$i]} )) DIFF=${DIFF#-} #get absolute value SUM=$(( $SUM + $DIFF )) #echo $SUM done echo $SUM