Re: ReadLines and Substraction

[Andres Perera]

On Mon, Mar 14, 2011 at 6:38 AM, pk <pk@pk.invalid> wrote:
> yetcom wrote:
>
>> Hello Everyone,
>>
>> I have an issue regarding the bash. I have 2 different files and each
>> of them involves some float point numbers for each lines. I want to
>> subtract each line then put all the results into a file. The first
>> line float number will be subtract with the first line of other file
>> and the second with the other second... and etc...
>>
>> When I read both files with:
>>
>> cat ./Temp1.log | while read line; do
>>
>>             cat ./Temp2.log | while read line; do
>>
>>             #It reads the first line of temp1, I also need to read the
>> first line of temp2. However, Temp2 will be read until the end of file
>> so that I cannot read one by one for each lines of different files.
>>
>>             done
>>
>> done
>>
>>
>> If you can help me with this, will be very happy for that. Thanks in
>> advance.

#!/usr/bin/env bash

set -e

if [[ $(type -t 'mapfile') != 'builtin' ]]
then
        function mapfile
        {
                while getopts C:c: f
                do
                        case $f in
                        C) cmd=$OPTARG;;
                        c) rep=$OPTARG;;
                        esac
                done
                shift $((--OPTIND))

                i=0
                while read -r n
                do
                        !((i % rep)) && eval "$cmd"
                        : $(($1[i++] = n))
                done
        }
fi

(((files = $#) >= 2))

while (($#))
do
        [[ $1 ]]
        mapfile -C'let ++lno #' -c1 par_$# < <(egrep '^[0-9]+$' "$1")
        shift
done

((lno && ((lno / files) == ${#par_1[@]})))

for i in ${!par_1[@]}; do
        for ((j=1; j <= files-1; j++)); do
                : $((par_$files[i] -= par_$j[i]))
        done
        printf '%d\n' $((par_$files[i]))
done

exit

>
> try
>
> paste -d '-' file1 file2 | bc > results
>
>
>