Hello obj-c, I just did my first obj-c app from Ubuntu with GNUStep ,see! Things you need to know to compile the hello world app with GNUStep:

1. sudo aptitude install gnustep gnustep-devel
2. chmod +x  /usr/share/GNUStep/MakeFiles/GNUStep.sh
3. /usr/share/GNUStep/MakeFiles/GNUStep.sh

source code here, very simple !

#import 
int main (void)
{
    NSLog (@"Hello obj-c !");
    return 0;
}

GNUMakeFile:

include $(GNUSTEP_MAKEFILES)/common.make

APP_NAME = HelloWorld
HelloWorld_HEADERS =
HelloWorld_OBJC_FILES = main.m
HelloWorld_RESOURCE_FILES =
include $(GNUSTEP_MAKEFILES)/application.make

that’s it !