Bash summing numbers in a file - bash

Question

I have a file which looks like this:
aaa 15
aaa 12
bbb 131
bbb 12
ccc 123
ddddd 1
ddddd 2
ddddd 3
I would like to get a sum for each unique element in the left side like this and also calculate the rounded percentage each of this represents out of the total:
aaa 27 - 9%
bbb 143 - 48%
ccc 123 - 41%
ddddd 6 - 2%
How would I accomplish this in BASH?

Answer 1

Since I cannot find any proper duplicate, I am posting an answer. Feel free to report a good one, so I will delete my answer and close as duplicate.
awk '{count[$1]+=$2} END {for (i in count) print i, count[i]}' file
This creates an array count[key]=value that keeps track of the value for a given key. Finally, it loops through the values and prints them.
It returns:
aaa 27
ccc 123
bbb 143
ddddd 6
To show percentages, just keep track of the total sum and divide accordingly:
awk '{tot+=$2; count[$1]+=$2}
END {for (i in count)
printf "%s %d - %d%%\n", i, count[i], (count[i]/tot)*100
}' file
So you can get:
aaa 27 - 9%
ccc 123 - 41%
bbb 143 - 47%
ddddd 6 - 2%

Answer 2

Since you asked for Bash, here's a Bash≥4 solution (needs Bash≥4 for associative arrays):
#!/bin/bash
declare -Ai sums
while read -r ref num; do
# check that num is a valid number or continue
[[ $num = +([[:digit:]]) ]] || continue
sums[$ref]+=$(( 10#$num ))
done < file
for ref in "${!sums[#]}"; do
printf '%s %d\n' "$ref" "${sums[$ref]}"
done
The output is not sorted; pipe through sort (or use a sorting algorithm) to sort it.
So now you added the percentage requirement! I hope you're not going to edit the question further adding more and more stuff…
Once we have the associative array sums, we can sum the sums:
sum=0
for x in "${sums[#]}"; do ((sum+=x)); done
and print the percentage:
for ref in "${!sums[#]}"; do
printf '%s %d - %d%%\n' "$ref" "${sums[$ref]}" "$((100*${sums[$ref]}/sum))"
done

Answer 3

And a solution for bash 3, without associative arrays:
while read key value
do
keys=$(echo -e "$keys\n$key")
var=data_$key
(($var=${!var}+$value))
((total=total+$value))
done < input_file
unique=$(echo "${keys:1}" | sort -u)
while read key
do
var=data_$key
((percentage=100*${!var} / total))
echo "$key $percentage%"
done <<EOF
$unique
EOF
Changed to use indirect variable references, rather than the more traditional eval.