我最近通过终端安装了Homebrew，但是当我尝试使用它安装其他程序时出现一些错误。
这是我尝试安装pyenv时的示例情况。
brew install pyenv
这是上述命令的输出：
Running `brew update --preinstall`...
Warning: No available formula with the name "ca-certificates".
==> Searching for similarly named formulae...
Error: No similarly named formulae found.
==> Searching for a previously deleted formula (in the last month)...
Error: No previously deleted formula found.
==> Searching taps on GitHub...
Error: No formulae found in taps.
Error:
homebrew-cask is a shallow clone.
To `brew update`, first run:
git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask fetch --unshallow
This command …