bash pipefail

If you care about the exit code of a piped bash command, you must set the "pipefail" option. The code below shows this.

	#!/bin/bash
	false; echo "false alone: $?"
	false | head; echo "false piped to head: $?"
	set -o pipefail
	false | head; echo "false 'pipefailed' to head: $?"

view raw bash-script-illustrating-pipefail.sh hosted with ❤ by GitHub

Output:

false alone: 1
false piped to head: 0
false 'pipefailed' to head: 1

The "take home" message from this is that you should always set the pipefail option. Too bad it is not the default.

Below are links to some other sites on this topic.

• pipefail – testing pipeline exit code
• pipefail