Calcul sur des colonnes dans le shell

[tmpfs]$ cat fich.txt
1 5.178
2 5.178
3 2.982
4 2.982
5 2.882
6 2.881
7 2.881
8 2.882
1 3.016
2 3.016
3 2.993
4 2.993
5 3.033
6 3.034
7 3.034
8 3.034

[tmpfs]$ cat foo.sh

#! /bin/bash

#set -x

nbre=$1
nbre2=$((nbre+1))

A=( $(sed -ne "1,$nbre s/.[^ ]*//p" fich.txt | sed ':b;N;$! bb;s/\n/ /g') )
B=( $(sed -ne "$nbre2,$ s/.[^ ]*//p" fich.txt | sed ':b;N;$! bb;s/\n/ /g') )

i=0
while [ "$i" -le "$((nbre-1))" ]
do
echo -e "$((i+1)) \c" && echo "${A[$i]} - ${B[$i]}" | bc
i=$((i+1))
done

[tmpfs]$ ./foo.sh 8
1 2.162
2 2.162
3 -.011
4 -.011
5 -.151
6 -.153
7 -.153
8 -.152

[tmpfs]$

#/usr/bin/bash

echo "Which file ?"
read file
NumberOfAtoms=`grep NumberOfAtoms ${file} |sed s/NumberOfAtoms//g`
NumberOfSpecies=`grep NumberOfSpecies ${file}|sed s/NumberOfSpecies//g`

rm FullUpDownList.tmp

NumberOfLinesToGrep=$((1+10*${NumberOfSpecies}+4+4*${NumberOfAtoms}+5))
egrep -B${NumberOfLinesToGrep} Relaxed ${file} | egrep -v "[yz]2|orb|MB|scaled|Qtot|Cr|Fe" | sed /^$/d  | sed /^...........................$/d | cut -d ' ' -f -6 | cut -d ' ' -f 4- | sed /^$/d  > FullUpDownList.tmp

nbre=$NumberOfAtoms
nbre2=$((NumberOfAtoms+1))

A=( $(sed -ne "1,$nbre s/.[^ ]*//p" FullUpDownList.tmp | sed ':b;N;$! bb;s/\n/ /g') )
B=( $(sed -ne "$nbre2,$ s/.[^ ]*//p" FullUpDownList.tmp | sed ':b;N;$! bb;s/\n/ /g') )

i=0
while [ "$i" -le "$((nbre-1))" ]
do
echo -e "$((i+1)) \c" && echo "${A[$i]} - ${B[$i]}" | bc >>
i=$((i+1))
done