Read the exit codes of a shell pipeline:

PIPESTATUS=(23 0)

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curl on the left, grep -q on the right. So: the download failed, the search

succeeded. grep found exactly what it was looking for — the page was there, the content

had rendered, everything was fine. And yet the if block around it declared "verification

failed" and turned the publish step red.

The pipeline sank precisely because it did its job. This article is about how that

sentence is possible, and why it is sitting in your verification code as a time bomb.

The incident first

6 August 2026, the editorial-series publishing workflow of this blog. After an article

goes out, one step verifies that the live page is really being served. Back then it

looked like this:

set -euo pipefail ...…