How to tee stderr from a trap?

Question

I want to log everything going to stderr in the following script:

#!/bin/bash
exec 2> >(tee -a file >&2)
trap '>&2 echo text; exit' INT
read

Pressing ctrl+c will trigger the trap, but the output is lost. Surprisingly, using exec 2>> file, it will end up in the file, yet I need it to be displayed to the user as well.

How can I log stderr, including the trap output, while still displaying it to the user?

Answer 1

In order for tee to ignore the interrupt signal one can add an additional trap '' INT before it:

#!/bin/bash
exec 2> >(trap '' INT; tee -a file >&2)
trap '>&2 echo text; exit' INT
read

Edit: Contained the trap in the subshell as sugested by @John1024 in the comments.