I have a Terraform string. It could be a var. or a local. or an output of some resource. I want to interpolate that string into another string with $ in front. Unfortunately,
"$${var.my_string}"
doesn't work because $${var.my_string} is the escape sequence that tells Terraform not to interpolate var.my_string.
How do I join $ onto the front of an interpolated value?
One way to do this is to interpolate two strings: the string "$" and the string you want:
"${"$"}${var.my_string}"
Additionally to @James' own answer, here are couple more ways to do it:
Unicode character escape sequence (0024 is the code for $): "\u0024${var.my_string}"
A strip marker in the interpolation: "$ ${~var.my_string}"
When a strip marker is present, any spaces adjacent to it in the corresponding string literal (if any) are removed before producing the final value.