发生冲突时，brew upgrade将停止。对于这种特殊情况，我将使用gnu parallel软件包中的parallel而不是moreutils中的软件包。最初安装它们时，我先安装了moreutils，然后强制安装了parallel。这种情况下的升级可以自动化吗？我不想总是手动进行此操作。
==> Upgrading parallel
Error: Cannot install parallel because conflicting formulae are installed.
moreutils: because both install a `parallel` executable.
Please `brew unlink moreutils` before continuing.
Unlinking removes a formula's symlinks from /usr/local. You can
link the formula again after the install finishes. You can --force this
install, but the build may fail or cause obscure side effects in the
resulting software.