make file for linux device driver

i was using RED HAT LINUX for device driver programming in class

now i install linux mint

i was previously used the make file for simple purposes

:)

obj-m := a1.o

all:

make -C /lib/modules/`uname -r`/build M=`pwd` modules

clean:

make -C /lib/modules/`uname -r`/build M=`pwd` clean

:cry:

but now it seems not working

may b silly mistakes

but i cant find it ,pls help me