Ruby；人；docs使用\"；

我正在阅读Ruby的"man"页面，我看到了下面对"-S"旗帜的描述:

-S   Makes Ruby use the PATH environment variable to search for script, unless its name begins with a slash.  This is used to emulate #! on
     machines that don't support it, in the following manner:

           #! /usr/local/bin/ruby
           # This line makes the next one a comment in Ruby \
           exec /usr/local/bin/ruby -S $0 $*

     On some systems $0 does not always contain the full pathname, so you need the -S switch to tell Ruby to search for the script if necessary
     (to handle embedded spaces and such).  A better construct than $* would be ${1+"$@"}, but it does not work if the script is being
     interpreted by csh(1).

让我感到困惑的是这一部分:

# This line makes the next one a comment in Ruby \
exec /usr/local/bin/ruby -S $0 $*

这听起来像是man条目的意思是，\字符导致它后面的行将被视为注释.

为了测试这一点，我try 创建了一个名为"foo.rb"的新Ruby脚本，其中包括这两行代码和一个简单的"PUTS"语句:

# This line makes the next one a comment in Ruby \
exec /usr/bin/env ruby -S $0 $*

puts "Hi"

我将脚本从/usr/local/bin/ruby更改为/usr/bin/env ruby，因为我没有位于/usr/local/bin的ruby可执行文件.我认为这不应该以一种有意义的方式影响结果，因为(根据文档)该行应该被视为注释，而不是可执行代码.

如果我对man条目的解释是正确的，那么当我运行"ruby foo.rb"时，我希望看到Hi输出到终端.但事实并非如此.相反，我看到了以下几点:

$ ruby foo.rb
foo.rb:2: unknown regexp option - b
exec /usr/bin/env ruby -S $0 $*
foo.rb:2: syntax error, unexpected local variable or method, expecting `do' or '{' or '('
exec /usr/bin/env ruby -S $0 $*
foo.rb:2: syntax error, unexpected global variable, expecting `do' or '{' or '('
exec /usr/bin/env ruby -S $0 $*

我做错了什么？