shell

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本文链接： https://blog.youkuaiyun.com/night_wisp/article/details/36210781

1.创建函数

function name {

         commands

}
也可以写成下面这种形式

name() {

         commands

}

2.函数返回值

函数退出状态是函数最后条命令返回的退出状态,可以用 $? 确定函数的退出状态

使用return:

#!/bin/bash
func1() {
read -p "Enter a value: " value
echo "the value times two"
return $[ $value * 2 ]
}

func1
echo "now value = $?"

使用函数的输出:

#!/bin/bash
func1() {
        read -p "Enter a value: " value
        echo $[ $value *2 ]
}

v1=func1
echo "v1 = $v1</span>"</span></code></pre><br><pre><codeclass="language-ruby">allen@ubuntu<spanclass="hljs-symbol">:/learnlinux</span>$ ./read.sh
Enter a value: 10
v1 = 20

3.在函数中使用变量

函数可以使用标准参数环境变量来表示命令行传递给函数的参数. 专用变量 $# 可以用来确定传递给函数的参数数目.

在脚本中指定函数时,必须在函数所在命令行提供参数 :  func1  $value1  10

#!/bin/bash
# passing parameters to a function

function addem {
if [ KaTeX parse error: Expected 'EOF', got '#' at position 1: #̲</span> -eq 0 ]…# -gt 2 ]
then
echo -1
elif [ $# -eq 1 ]
then
echo $[ $1 + $1 ]
else
echo $[ $1 + $2 ]
fi
}

echo -n "Adding 10 and 15: "
value=addem 10 15
echo $value</span><spanclass="hljs-buil{t}_{i}n">echo</span>-n<spanclass="hljs-string">"Le{t}^{\prime }stryaddingjustonenumber:"</span>value=‘addem10‘<spanclass="hljs-buil{t}_{i}n">echo</span><spanclass="hljs-variable">$value
echo -n "Now trying adding no number: "
value=addem
echo $value</span><spanclass="hljs-buil{t}_{i}n">echo</span>-n<spanclass="hljs-string">"Finally,tryaddingthreenumbers:"</span>value=‘addem101520‘<spanclass="hljs-buil{t}_{i}n">echo</span><spanclass="hljs-variable">$value

allen@ubuntu:~/learnlinux/UNIX$ ./func.sh

Adding 10 and 15: 25

Let’s try adding just one number: 20

Now trying adding no number: -1

Finally, try adding three numbers: -1