0999: Value too great for base (error token is "0999")

This is a shortened-version of a script for reading 8mm tapes from a EXB-8500 with an autoloader (only 10 tapes at a time maximum) attached. It dd's in tape data (straight binary) and saves it to files that are named after the tape's 4-digit number (exmaple D1002.dat) in both our main storage and our backup. During this time it's logging info and displaying its status in the terminal so we can see how far along it is.

#!/bin/bash
echo "Please enter number of tapes: [int]"
read i
j=1
until [ $i -lt $j ]
do
    echo "What is the number of tape $j ?"
    read Tape_$j
    (( j += 1 ))
done
echo "Load tapes into the tower and press return when the drive is ready"
read a
j=1
until [ $i -lt $j ]
do
    k="Tape_$j"
    echo "tower1 $j D$(($k)) `date` Begin"
    BEG=$j" "D$(($k))" "`date`" ""Begin"
    echo "tower1 $j D$(($k)) `date` End"
    END=$j" "D$(($k))" "`date`" ""End"
    echo "$BEG      $END"
    echo "$BEG      $END"
    sleep 2
    (( j += 1 ))
done
echo "tower1 done"

Everything was hunky-dory until we got under 1000 (startig at 0999). Error code was ./tower1: 0999: Value too great for base (error token is "0999"). Now I already realize that this is because the script is forcing octal values when I type in the leading 0, and I know I should insert a 10# somewhere in the script, but the question is: Where?

Also is there a way for me to just define Tape_$j as a string? I feel like that would clear up a lot of these problems

To get the error, run the script, define however many tapes you want (at least one, lol), and insert a leading 0 into the name of the tape

EXAMPLE:

./test
Please enter number of tapes: [int]
1
What is the number of tape 1?
0999

./test: 0999: Value too great for base (error token is "0999")

Solution

You don't want to use $k as a number, but as a string. You used the numeric expression to evaluate a variable value as a variable name. That's very bad practice.

Fortunately, you can use variable indirection in bash to achieve your goal. No numbers involved, no error thrown.

echo "tower1 $j ${!k} `date` Begin"
BEG=$j" "D${!k}" "`date`" ""Begin"

And similarly in other places.