Fail on pattern match of output while showing output. zsh + macOS compatible

failon.sh

# Allow failing on regex pattern match
# See https://superuser.com/a/1717757/60337
failon() (
  pattern="$1"
  shift
  [ "$#" -eq 0 ] && set cat
  FAILON_STATUS="${FAILON_STATUS:-125}"
  set -o pipefail
  { "$@" \
    | "$@" >&3 \
    | { grep -q -- "$pattern" && return "$FAILON_STATUS" || return 0; }
  } 3>&1
)