下載地址

1. 打開iTerm，輸入mkdir ~/bin，在當前用戶根目錄下創建一個bin目錄；
2. 把class-dump給拷貝到這個目錄裏，mv /path/to/class-dump ~/bin
3. 並賦予其可執行權限： chmod +x ~/bin/class-dump
4. 打開~/.bash_profile文件：vi ~/.bash_profile， 在文件最上方加一行：export PATH=$HOME/bin/:$PATH，然後保存並退出（在英文輸入法中依次按下esc和:（shift + ;，即冒號），然後輸入wq，回車即可）；
5. 在iTerm中執行source ~/.bash_profile

　　測試

localhost:~ sky$ pwd class-dump
/Users/sky
localhost:~ sky$ class-dump
class-dump 3.5 (64 bit)
Usage: class-dump [options] <mach-o-file>

  where options are:
        -a             show instance variable offsets
        -A             show implementation addresses
        --arch <arch>  choose a specific architecture from
 
 a universal binary (ppc, ppc64, i386, x86_64, armv6, armv7, armv7s, arm64)
        -C <regex>     only display classes matching regular expression
        -f <str>       find string in method name
        -H             generate header files in current directory, or directory specified with -o
        
 
-I             sort classes, categories, and protocols by inheritance (overrides -s)
        -o <dir>       output directory used for -H
        -r             recursively expand frameworks and fixed VM shared libraries
        -s             sort classes and categories by name
        -S             sort methods by name
        -t             suppress header in output, for testing
        --list-arches  list the arches in the file, then exit
        --sdk-ios      specify iOS SDK version (will look in /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS<version>.sdk
        --sdk-mac      specify Mac OS X version (will look in /Developer/SDKs/MacOSX<version>.sdk
        --sdk-root     specify the full SDK root path (or use --sdk-ios/--sdk-mac for a shortcut)
localhost:~ sky$

解決

安裝class-dump