Bash: handling "[[ statement ]] || echo problem found ; exit 1" logic

Question

In the statement in the title, there is a problem that even if the statement is true, it will still exit with status 1 because, as I understand it:

[[ statement ]] || echo problem found ; exit 1

Evaluates to if the statement is false, echo problem found. Exit with status 1. Even if the statement evaluates true, the exit 1 still happens because it is separate. I thought to fix this by running it in a subshell like so:

[[ statement ]] || (echo problem found ; exit 1)

This seems to do what I want, but is it an acceptable way to handle this?

Answer 1

You must use

[[ statement ]] || { echo problem found ; exit 1; }

The difference is that the brace syntax doesn't create a subshell, which means the exit 1 applies to the current shell. If you use (exit 1) the subshell exits but the current shell continues running.

Answer 2

You need to use syntax like this :

[[ statement ]] || { echo problem found ; exit 1; }

and more accurate send standard error

[[ statement ]] || { echo >&2 "problem found"; exit 1; }

Answer 3

Don't try to be clever. Remember that debugging is twice as hard as writing, so when you're writing a program, be only half as clever as you can be.

if ! [[ statement ]]; then
  echo problem found
  exit 1
fi