Checking for same file

I was wondering if there is a way to to check if two files are the same. I've tried writing a script called samefile, which takes in two arguments (files) and attempts to compare them to see if they're the same file.

Here is what I have so far:

if [ $1 != $2 ]
then
     echo "The two files are not the same!" 
     exit 1
elif [ $1 = $2 ]
    echo "The two files are the same!"
    exit 1
fi

Here's the output I'm getting:

samefile abc abc
-bash: test: abc: unary operator expected