shell变量作用域

#!/bin/sh
# childDemo.sh

echo "`basename ${0}` the variables is: "
echo "A:  $A"
echo "Welcome: $Welcome"
echo "Author: $Author"
echo "Version $Version"

#!/bin/sh
# parentDemo.sh

export Welcome="Hello variables"
Author="Lesus"
Version=0.1

localF(){
    local A=10
    Version=0.2
    echo "A:  $A"
    echo "Welcome：$Welcome"
    echo "Author:  $Author"
    echo "Version:  $Version"
}

echo "call localF function"
localF

echo "========================"

echo "Now the variables is: "
echo "A:  $A"
echo "Welcome: $Welcome"
echo "Author: $Author"
echo "Version $Version"

echo "========================"

echo "Using default"
./childDemo.sh

echo "========================"

echo "Using source"
. ./childDemo.sh

echo "======================="

echo "Using exec"
exec ./childDemo.sh

好了，相关材料都齐全了，

关于默认的执行脚本方式，source和exec方式我会在下一篇里介绍。最好在理解了这三者的关系，对作用域才会有更好的理解。

现在总结一下：

作用域关键字有三个: 范围从大到小依次是 

export        作用域范围为本身shell和它的子shell中

默认            作用域范围为本身shell

local            作用域范围为本身shell中特定的范围