Shell之Function与Source

Shell之Function与Source

Written by Zak Zhu

学习python风格, 优雅规范书写shell代码

参考

• 菜鸟教程/Shell 函数(https://www.runoob.com/linux/linux-shell-func.html)
• C语言中文网/Shell函数: Shell函数返回值, 删除函数, 在终端调用函数(http://c.biancheng.net/cpp/view/7011.html)

Fuction的编写

函数语法

定义格式:

[function] foo() {
    COMMANDS
    [return N]      # 返回码(N)的取值范围: 0~255
}

调用格式:

foo [ARGS]

实例:

# Defined function
function hello() {
    echo "Hello World !"
}

# Invoke function
hello

函数传参

实例:

function two_num_sum() {
    let sum=$1+$2
    return ${sum}
}

read -p "Please input the first number: " arg1
read -p "Please input the second number: " arg2
two_num_sum ${arg1} ${arg2}
ret=$?
echo "The sum of two numbers is ${ret}"

Source的使用

和其他语言一样, Shell也可以包含外部脚本. 这样可以很方便的封装一些公用的代码作为一个独立的文件.

实例:

• functions.sh文件:

  function hello() {
      echo "Hello World !"
  }
  
  function two_num_sum() {
      let sum=$1+$2
      return ${sum}
  }

• bin.sh文件:

  #!/bin/bash
  
  #####################################
  # @Author: 
  # @Created Time: 2019-10-01 02:07:32
  # @Description: 
  #####################################
  
  
  source ./functions.sh
  
  hello
  
  read -p "Please input the first number: " arg1
  read -p "Please input the second number: " arg2
  two_num_sum ${arg1} ${arg2}
  ret=$?
  echo "The sum of two numbers is ${ret}"
  

执行bin.sh的结果: