On Oct 25, 2017, at 10:02 AM, Mark Haney <mark.ha...@neonova.net> wrote:
>
> I have a file with two columns 'email' and 'total' like this:
>
> m...@example.com 20
> m...@example.com 40
> y...@domain.com 100
> y...@domain.com 30
>
> I need to get the total number of messages for each email address.
This screams out for associative arrays. (Also called hashes, dictionaries,
maps, etc.)
That does limit you to CentOS 7+, or maybe 6+, as I recall. CentOS 5 is
definitely out, as that ships Bash 3, which lacks this feature.
#!/bin/bash
declare -A totals
while read line
do
IFS="\t " read -r -a elems <<< "$line"
email=${elems[0]}
subtotal=${elems[1]}
declare -i n=${totals[$email]}
n=n+$subtotal
totals[$email]=$n
done < stats
for k in "${!totals[@]}"
do
printf "%6d %s\n" ${totals[$k]} $k
done
You’re making things hard on yourself by insisting on Bash, by the way. This
solution is better expressed in Perl, Python, Ruby, Lua, JavaScript…probably
dozens of languages.
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