first&second

---

first:

#!/bin/bash
film="the first film"
echo "$film"
./second #创建子进程运行second，在子进程地址空间运行second
echo "$film"

second:

#!/bin/bash
echo "$film"
film="the second film"
echo "$film"

---

对first、second添加可执行权限后
执行

./first

结果

the first film

the second film
the first film

---

将first改成

#!/bin/bash
film="the first film"
echo "$film"
. ./second #父进程运行second，在父进程地址空间运行second
echo "$film"

执行

./first

结果

the first film
the first film
the second film
the second film

---

---

将first改成

#!/bin/bash
film="the first film"
echo "$film"
export film
./second #创建子进程运行second，在子进程地址空间运行second
echo "$film"

执行

./first

结果

the first film
the first film
the second film
the first film

---

将first改为

#!/bin/bash
film="the first film"
echo "$film"
#export film
film= `./second`
echo "$film"

将second改为

#!/bin/bash
#echo "$film"
film="the second film"
echo "$film"

执行

./first

结果

the first film
the second film #the second film被返回