How can I make a multiplication table using bash brace expansion? So far I have this: echo $[{1..10}*{1..10}]

Question

I am trying to learn bash at a deeper level, and I decided to make a multiplication table. I have the functionality with the statement :

echo $[{1..10}*{1..10}]

but that gives me the following output:

1 2 3 4 5 6 7 8 9 10 2 4 6 8 10 12 14 16 18 20 3 6 9 12 15 18 21 24 27 30 4 8 12 16 20 24 28 32 36 40 5 10 15 20 25 30 35 40 45 50 6 12 18 24 30 36 42 48 54 60 7 14 21 28 35 42 49 56 63 70 8 16 24 32 40 48 56 64 72 80 9 18 27 36 45 54 63 72 81 90 10 20 30 40 50 60 70 80 90 100

Is there any way to format this output like the following using only 1 statement (i can figure out how to do this with loops, but that's no fun :p )

1 2 3 4 5 6 7 8 9 10 
2 4 6 8 10 12 14 16 18 20 
3 6 9 12 15 18 21 24 27 30 
4 8 12 16 20 24 28 32 36 40 
5 10 15 20 25 30 35 40 45 50 
6 12 18 24 30 36 42 48 54 60 
7 14 21 28 35 42 49 56 63 70 
8 16 24 32 40 48 56 64 72 80 
9 18 27 36 45 54 63 72 81 90 
10 20 30 40 50 60 70 80 90 100

Is it even possible to do in one statement, or would I have to loop?

Answer 1

Use this line for a nice output without using loops:

echo $[{1..10}*{1..10}] | xargs -n10 | column -t

Output:

1   2   3   4   5   6   7   8   9   10
2   4   6   8   10  12  14  16  18  20
3   6   9   12  15  18  21  24  27  30
4   8   12  16  20  24  28  32  36  40
5   10  15  20  25  30  35  40  45  50
6   12  18  24  30  36  42  48  54  60
7   14  21  28  35  42  49  56  63  70
8   16  24  32  40  48  56  64  72  80
9   18  27  36  45  54  63  72  81  90
10  20  30  40  50  60  70  80  90  100

---

Update

As a logical next step, I asked here if this multiplication table can have a variable range. With this help, my answer works with a variable ($boundary) range and stays quite readable:

boundary=4; eval echo $\[{1..$boundary}*{1..$boundary}\] | xargs -n$boundary | column -t

Output:

1  2  3   4
2  4  6   8
3  6  9   12
4  8  12  16

Also note that the $[..] arithmetic notation is deprecated and $((...)) should be used instead:

boundary=4; eval eval echo "$\(\({1..$boundary}*{1..$boundary}\)\)" | xargs -n$boundary | column -t

Answer 2

The printf built-in repeats its format as many times as necessary to print all arguments, so:

printf '%d %d %d %d %d %d %d %d %d %d\n' $[{1..10}*{1..10}]

If you want to avoid repeating the %d bit, it's trickier.

printf "$(echo %$[{1..10}*0]d)\\n" $[{1..10}*{1..10}]

In production code, use a loop.