Comment 3 for bug 1394136

This is not a bug, although some might disagree with the current behavior of bash.

With a command like 'yes | grep -q .', because the grep terminates early and the yes is writing past the end of the pipe buffer, the yes process is _always_ terminated with a SIGPIPE signal (which translates to a return value of 141). Combined with the pipefail option, the whole command is considered to have failed.

pipefail should be used scarcely, that's why it is not enabled by default.