什么是Shell

  • 有Kernel就有Shell,核与壳
  • 用户同计算机交互,用户访问操作系统服务的接口
  • 广义,用户接口;狭义,命令行

In computing, a shell is a user interface for access to an operating system's services. In general, operating system shells use either a command-line interface (CLI) or graphical user interface (GUI), depending on a computer's role and particular operation. It is named a shell because it is the outermost layer around the operating system kernel.

什么是Shell编程

  • 命令行胶水语言
  • 超高级程序语言:可以直接通过命令行调用其他程序语言写的程序
  • 自动化

tips

no space around the sign "=" when assigning a value to a variable

space, not , when compound assign an array