你在回避这个问题。并不是每个人都认为shell语言更好。首先，_为什么不呢

Not long ago a friend asked me how to recursively search his PHP scripts for a string. He had a lot of big binary files and templates in those directories that could have really bogged down a plain grep. I couldn't think of a way to use grep to make this happen, so I figured using find and grep together would be my best bet. find . -name "*.php" -exec grep 'search_string' {} \; -print Here's the above file search reworked in Ruby: Dir['**/*.php'].each do |path| File.open( path ) do |f| f.grep( /search_string/ ) do |line| puts path, ':', line end end end Your first reaction may be, "Well, that's quite a bit wordier than the original." And I just have to shrug and let it be. "It's a lot easier to extend," I say. And it works across platforms.

我认为这是一个分析的问题。Shell语言默认假设普通的$ xxx命令意味着要运行的命令。在Python和Ruby中需要你做系统(“命令”)或其他什么。

并不是说它们不合适，只是还没有人真正做过;至少我是这么认为的。Rush是Ruby中的一个例子，Python有IPython或类似的东西。

No.

不，脚本语言可能不适合shell。

问题在于宏语言和其他所有语言之间的二分法。

shell与其他遗留宏语言(如nroff和m4)属于一类。在这些处理器中，所有内容都是字符串，处理器定义了从输入字符串到输出字符串的映射。

在所有语言中，某些边界都是双向交叉的，但通常很清楚系统的类别是宏观的还是，嗯，我不知道有一个官方术语……我会说“一种真正的语言”。

当然，您可以用Ruby这样的语言输入所有的命令，它甚至可能是仅次于真正shell的次优选择，但它永远不会是宏语言。有太多的语法需要考虑。它需要太多的引号。

但是在开始使用宏语言编程时，宏语言也有它自己的问题，因为必须做出太多妥协才能摆脱所有语法。输入字符串时不带引号。需要重新引入各种神奇的方法来注入缺失的语法。我在nroff做过一次code-golf，就是为了与众不同。这很奇怪。宏语言中大型实现的源代码是可怕的。

shell语言必须易于使用。您希望键入一次性的丢弃命令，而不是小程序。也就是说，你想要打字

ls -laR /usr

not

shell.ls("/usr", long=True, all=True, recursive=True)

这(也)意味着shell语言并不真正关心参数是选项、字符串、数字还是其他东西。

此外，shell中的编程构造是一个附加组件，甚至不总是内置的。例如，考虑Bash或Bourne shell (sh)中if和[的组合，用于生成序列的seq，等等。

最后，shell具有在编程中较少或不同的特定需求。例如，管道、文件重定向、进程/作业控制等等。

由于这两种语言都是正式的编程语言，所以在一种语言中可以做的事情，在另一种语言中也可以做。实际上，这是一个设计重点问题。Shell语言是为交互使用而设计的，而脚本语言不是。

The basic difference in the design is the storage of data between commands and the scope of variables. In Bash, etc. you have to jump through hoops to store a value (for example, commands like set a='something'), while in languages like Python you simply use an assignment statement (a = 'something'). When using the values in a shell language you have to tell the language that your want the value of the variable, while in scripting languages you have to tell the language when you want the immediate value of the string. This has effects when used interactively.

在脚本语言中，ls被定义为命令

a = some_value

ls a*b  

(a是什么意思?这意味着some_value *(不管b是什么)还是你的意思 “'anystring b ?。在脚本语言中，默认值是存储在内存中的。)

ls 'a*b'  Now means what the Unix ls a*b means.

用类似bash的语言

set a=some_value

ls a*b   means what the Unix ls a*b means.

ls $a*b  uses an explicit recall of the value of a.

脚本语言使得存储和检索值变得容易，而值上的瞬态作用域却很难实现。Shell语言可以存储和调用值，但是每个命令的作用域都是短暂的。

你在回避这个问题。并不是每个人都认为shell语言更好。首先，_为什么不呢

Not long ago a friend asked me how to recursively search his PHP scripts for a string. He had a lot of big binary files and templates in those directories that could have really bogged down a plain grep. I couldn't think of a way to use grep to make this happen, so I figured using find and grep together would be my best bet. find . -name "*.php" -exec grep 'search_string' {} \; -print Here's the above file search reworked in Ruby: Dir['**/*.php'].each do |path| File.open( path ) do |f| f.grep( /search_string/ ) do |line| puts path, ':', line end end end Your first reaction may be, "Well, that's quite a bit wordier than the original." And I just have to shrug and let it be. "It's a lot easier to extend," I say. And it works across platforms.