What kind of suspicious text are you looking for?
If you just want to see if it's changed, you can first look at the time stamp and size of the file.
Keep in mind, though that those can be tricky, and won't always tell you of a problem. If you're the administrator of the system, perhaps you might find a tool like
tripwire usefull. Otherwise, you'll probably have to check for changes manually, using tools like chksum, md5sum, etc...
Keep in mind that you have to start out with a clean copy to get the correct values from, and you can't store the values on the Unix box.
But if you're looking for something specific, let us know