出现这个问题，一种的path路径不对，路径不对，修改路径；路径修改传送门：zsh: command not found解决方法：配置环境变量
另一种原因可能是没有该命令的相关安装包：
没有安装包时，采用brew命令安装.

如安装wget

brew install wget

ps:
如果brew安装出现以下错误：

Updating Homebrew...
Error: No available formula with the name "service"
==> Searching for a previously deleted formula (in the last month)...
Warning: homebrew/core is shallow clone. To get complete history run:
  git -C "$(brew --repo homebrew/core)" fetch --unshallow

Error: No previously deleted formula found.
==> Searching for similarly named formulae...
These similarly named formulae were found:
gst-editing-services                                              kubernetes-service-catalog-client
To install one of them, run (for example):
  brew install gst-editing-services
==> Searching taps...
==> Searching taps on GitHub...
Error: No formulae found in taps.

可采用以下方法尝试：

rm -rf /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core; brew update