Ubuntu

Hi all, I'm a newbie in shell scripting and currently I'm trying to create a matrix using bash. The Output will look like this

AB CDE FG

1
2
3
4
5
6
7

I'm stuck on the ABCDEFG display.

printFlightSeats()
{

rows=7
columns=7
for ((i=0;i<=$rows;i++))
do
echo -n "$i" | tr "0" " "
for ((j=0;j<$columns;j++))
do
echo -n "$j" | tr "0" " " | tr "1234567" "ABCDEFG"

done
printf $j
printf "$i\n"
done

}

Can anyone advise me? Thanks in advance!

Moderator's Comments:

Double post, continued here