何为 PATH？

PATH 路径是环境变量，和 Windows 系统类似，是可执行命令文件的存放路径。

当你在命令行输入一个 ls 命令时，系统会在当前工作目录以及 PATH 的路径中依次寻找，找到的话执行，找不到的话返回 command not found: ls。

PATH 路径可以通过 echo $PATH 查看，

或者 env|grep PATH。

修改 PATH

添加

• 临时添加 usr/local/bin

  直接在终端输入命令 PATH=$PATH:/usr/local/bin

  更改在当前会话有效，退出本次会话后则失效

• 永久添加 usr/local/bin

  修改 .bashrc 文件

  添加一句：export PATH=$PATH:/usr/local/bin

删除

• 临时删除

  直接在终端输入命令 PATH=... ...为除去不想要的路径的其他所有路径

• 永久删除

  • 将上面的临时命令放入 .bashrc 中：echo PATH=...
    或者在 .bashrc 文件末尾添加以下代码：

  ### remove unnecessary Win PATHs
  # This can prevent extension-less commands from bleeding into BASH.
  # (eg. "ng" would execute the Win bin if "@angular/cli" wasn't installed on Linux.)
  #
  function path_remove {
    # Delete path by parts so we can never accidentally remove sub paths
    PATH=${PATH//":$1:"/":"} # delete any instances in the middle
    PATH=${PATH/#"$1:"/} # delete any instance at the beginning
    PATH=${PATH/%":$1"/} # delete any instance in the at the end
  }
  
  path_remove '/mnt/c/Users/me/AppData/Roaming/npm'
  path_remove '/mnt/c/Users/me/AppData/Local/Yarn/bin'
  path_remove '/mnt/c/Program Files (x86)/Yarn/bin'
  path_remove '/mnt/c/Program Files/Git'
  path_remove '/mnt/c/Program Files/Git/cmd'
  path_remove '/mnt/c/Program Files/nodejs'
  path_remove '/mnt/c/OpenSSL-Win32/bin'
  path_remove '/mnt/c/Program Files (x86)/Python27'