seq - How to produce cartesian product in bash?

Question

I want to produce such file (cartesian product of [1-3]X[1-5]):

1 1
1 2
1 3
1 4
1 5
2 1
2 2
2 3
2 4
2 5
3 1
3 2
3 3
3 4
3 5

I can do this using nested loop like:

for i in $(seq 3) 
do
  for j in $(seq 5)
  do
      echo $i $j
  done
done

is there any solution without loops?

Answer 1

Combine two brace expansions!

$ printf "%s
" {1..3}" "{1..5}
1 1
1 2
1 3
1 4
1 5
2 1
2 2
2 3
2 4
2 5
3 1
3 2
3 3
3 4
3 5

This works by using a single brace expansion:

$ echo {1..5}
1 2 3 4 5

and then combining with another one:

$ echo {1..5}+{a,b,c}
1+a 1+b 1+c 2+a 2+b 2+c 3+a 3+b 3+c 4+a 4+b 4+c 5+a 5+b 5+c