How do I assign something to a JQ variable I've already set in JQ?

Question

I'm setting some variables before I run a JQ that I want to set some fields to. Like so:

jq --arg user $SOME_USER '.something.user|="$user Did a thing"'

But when I pipe this to a file or look at stdout it seems to pick up the variable but not replace it in the string in the JQ script.

Answer 1

jq does do variable interpolation; the syntax is just a little different from other languages. You have to explicitly request interpolation with \\(...) .

jq --arg user "$SOME_USER" '.something.user|="\($user) did a thing"'

Answer 2

I was dumb as a stack of bricks. JQ doesn't render variables in strings in the same way as some languages will do. In my case, I could simply have kept the variable out of the string and written: $user + "...".