I have two lists
A='"foo" "bar"'
foo='"alpha" "beta"'
bar='"gamma" "delta"'
I want to iterate over list A and in a nested loop iterate over lists foo and bar so that i can execute a command in the nested loop where i can execute a commands like
./submit_to_cluster --x=foo --y=alpha
./submit_to_cluster --x=bar --y=delta
Is the iteration over the two lists in a nested manner the best way to do this efficiently?
In your example A is not a list. If you need a list, use a list. This is a list: A=(foo bar). And this is how to reference an array: ${A[@]}.
What you are looking for is called indirect referencing. You have the name of a variable in a variable. This is indirect referencing: ${!v}.
You problem is: how to refer indirectly to an array?
This question has already been answered: How to iterate over an array using indirect reference?
This shows how to apply the answer to your example:
A=("foo" "bar")
foo=("alpha" "beta")
bar=("gamma" "delta")
for x in "${A[@]}"; do
xa="${x}[@]"
for y in "${!xa}"; do
echo ./submit_to_cluster --x="$x" --y="$y"
done
done
This prints:
./submit_to_cluster --x=foo --y=alpha
./submit_to_cluster --x=foo --y=beta
./submit_to_cluster --x=bar --y=gamma
./submit_to_cluster --x=bar --y=delta
