How to concatenate variables in nginx?

Question

Nginx

You need to upload a video, but before that you need to upload a cover for the video, for this you need to add the word "cover" to the file name. I do it like this:

location /get {
     root /path/to/file/$arg_name+cover

This code does not work, so I have a question, how can strings be combined in nginx?

Answer 1

This is how it should work:
root /path/to/file/${arg_name}cover