Sorry I know this has been covered all over the place, only I can't fix this to save my life.
If someone could explain clearly what I might have done and what I might be able to do to fix this I would be forever grateful.
Here is my error:
Command /Xcode 4/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1
ld: duplicate symbol _OBJC_IVAR_$_sunnyHillsTL._tileMap in /Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Products/Debug-iphoneos/libcocos2d libraries.a(sunnyHillsTL.o) and /Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Intermediates/workingTitle.build/Debug-iphoneos/workingTitle.build/Objects-normal/armv7/sunnyHillsTL.o
Ld /Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Products/Debug-iphoneos/workingTitle.app/workingTitle normal armv7
cd "/Users/kahanejosh/Documents/iPhone:Mac Dev/Working Title/workingTitle"
setenv IPHONEOS_DEPLOYMENT_TARGET 3.0
setenv PATH "/Xcode 4/Platforms/iPhoneOS.platform/Developer/usr/bin:/Xcode 4/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
"/Xcode 4/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2" -arch armv7 -isysroot "/Xcode 4/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk" -L/Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Products/Debug-iphoneos -F/Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Products/Debug-iphoneos -filelist /Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Intermediates/workingTitle.build/Debug-iphoneos/workingTitle.build/Objects-normal/armv7/workingTitle.LinkFileList -dead_strip -all_load -ObjC -miphoneos-version-min=3.0 -framework CoreGraphics -framework Foundation -framework OpenGLES -framework QuartzCore -framework UIKit -framework AudioToolbox -framework OpenAL -lz -framework AVFoundation "-lcocos2d libraries" -o /Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Products/Debug-iphoneos/workingTitle.app/workingTitle
ld: duplicate symbol _OBJC_IVAR_$_sunnyHillsTL._tileMap in /Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Products/Debug-iphoneos/libcocos2d libraries.a(sunnyHillsTL.o) and /Users/kahanejosh/Library/Developer/Xcode/DerivedData/workingTitle-cawhuhbkmwcesmbqxvkbkbatdbze/Build/Intermediates/workingTitle.build/Debug-iphoneos/workingTitle.build/Objects-normal/armv7/sunnyHillsTL.o
collect2: ld returned 1 exit status
Command /Xcode 4/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1
It looks like you have two targets set up and your source is getting used in both. So, you create a static library with the sunnyHillsTL class that gets put into libcocoas2d libraries.a and then you are using the same object file as well. Either don't directly use the class in your target (don't add the class to the target) if you're using the library, or don't have this class be compiled as part of the static library.
Seems like you have two instance variables named «tileMap» in your «sunnyHillsTL» class...
install Command Line Tools from your Xcode. in Xcode -> Preferences -> Downloads -> Components ->Command Line Tools
来源：https://stackoverflow.com/questions/5148466/xcode-exit-code-1-duplicate-symbol