class-dump is a command-line utility for
examining the Objective-Csegment of Mach-O files. It generates
declarations for the classes,categories and protocols. This is the same
information provided byusing ‘otool -ov’, but presented as normal
Objective-C declarations.
1.下载安装包
http://stevenygard.com/projects/class-dump/，
这里我下载的是 class-dump-3.5.dmp。然后把
放到/usr/local/bin目录下，在终端输入class-dump，显示 class-dump的版本后，就可以正常使用 class-dump 命令了。正确安装后如下图所示：
2.使用方法
命令如下：class-dump -H /Applications/Calculator.app -o /Users/apple/Desktop/calculate\ heads
解释：
/Applications/Calculator.app是计算器app的路径
/Users/apple/Desktop/calculate\ heads是存放dump出来头文件的文件夹路径
结果如下：
利用 class-dump 可以导出 AppKit，UIKit。。。
class-dump AppKit:class-dump /System/Library/Frameworks/AppKit.framework
class-dump UIKit:class-dump /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/System/Library/Frameworks/UIKit.framework
原文引自：https://cnbin.github.io/blog/2015/05/21/objective-c-class-dump-an-zhuang-he-shi-yong-fang-fa/
