Return将导致当前函数超出作用域，而exit将导致脚本在调用它的地方结束。下面是一个示例程序来帮助解释这一点:

#!/bin/bash

retfunc()
{
    echo "this is retfunc()"
    return 1
}

exitfunc()
{
    echo "this is exitfunc()"
    exit 1
}

retfunc
echo "We are still here"
exitfunc
echo "We will never see this"

输出

$ ./test.sh
this is retfunc()
We are still here
this is exitfunc()

简单来说(主要针对编程新手)，我们可以说:

    `return`: exits the function,
    `exit()`: exits the program (called as process while running)

如果你观察一下，这是非常基本的，但是…

    `return`: is the keyword
    `exit()`: is the function

如果将Bash脚本转换为函数，则通常将退出N替换为返回N。调用该函数的代码将把返回值视为子进程的退出代码。

在函数中使用exit将强制整个脚本结束。

Return将导致当前函数超出作用域，而exit将导致脚本在调用它的地方结束。下面是一个示例程序来帮助解释这一点:

#!/bin/bash

retfunc()
{
    echo "this is retfunc()"
    return 1
}

exitfunc()
{
    echo "this is exitfunc()"
    exit 1
}

retfunc
echo "We are still here"
exitfunc
echo "We will never see this"

输出

$ ./test.sh
this is retfunc()
We are still here
this is exitfunc()

在其他一些答案中添加一个可操作的方面:

两者都可以给出退出代码- default或由函数定义，并且唯一的“default”是零，表示成功退出和返回。任何状态都可以有一个自定义数字0-255，包括成功。

返回通常用于运行在当前shell中的交互式脚本，称为with。例如Script.sh，它只是将您返回到调用shell。然后，调用shell可以访问返回代码- $?给出定义的返回状态。 在这种情况下，Exit还会关闭shell(包括SSH连接，如果这是您的工作方式的话)。

如果脚本是可执行的，并且从另一个脚本或shell调用并且在子shell中运行，那么Exit是必要的。然后退出码可以被调用shell访问-在这种情况下return会给出一个错误。

OP的问题是: BASH函数中的返回语句和退出语句在退出代码方面有什么区别?

首先，需要做一些澄清:

A (return|exit) statement is not required to terminate execution of a (function|shell). A (function|shell) will terminate when it reaches the end of its code list, even with no (return|exit) statement. A (return|exit) statement is not required to pass a value back from a terminated (function|shell). Every process has a built-in variable $? which always has a numeric value. It is a special variable that cannot be set like "?=1", but it is set only in special ways (see below *). The value of $? after the last command to be executed in the (called function | sub shell) is the value that is passed back to the (function caller | parent shell). That is true whether the last command executed is ("return [n]"| "exit [n]") or plain ("return" or something else which happens to be the last command in the called function's code.

在上面的项目符号列表中，从"(x|y)"中选择，要么总是第一项，要么总是第二项，分别获得关于函数和return的语句，或者shell和exit的语句。

很明显，它们都使用了特殊变量$?在值终止后向上传递值。

*现在是$?可设置:

When a called function terminates and returns to its caller then $? in the caller will be equal to the final value of $? in the terminated function. When a parent shell implicitly or explicitly waits on a single sub shell and is released by termination of that sub shell, then $? in the parent shell will be equal to the final value of $? in the terminated sub shell. Some built-in functions can modify $? depending upon their result. But some don't. Built-in functions "return" and "exit", when followed by a numerical argument both set $? with their argument, and terminate execution.

值得注意的是，$?可以通过在子shell中调用exit来赋值，如下所示:

# (exit 259)
# echo $?
3