This may/may not be a long answer to a short question.
I am learning the C programming language at home.I have seen some good books on the UNIX programming enviroment.However, there were a few books that hinted towards the Linux programming enviroment.Is there any difference between the two as far as programming is concerned?
Thank you in advance for your help
no significant difference..... Linux tends to be more open and less expensive... UNIX systems tend to be more commerical and less open. However, there are exceptions.
The main 'big business' difference is solely based on 'who wrote what kernel code when' and is more to do with big business and legalese... and very little to do with technology. They all use C as the underlying language for the kernal and have a similar design philosophy.
UNIX is generic, regardless of what some companies in the UK would like people to believe. There are generic classes on UNIX, generic books, generic applications, generic utilities, etc.
If you are a wiz at one, you are a wiz at the other..... 
In fact, mature UNIX/LINUX users are very comfortable with both because both are a form of the generic UNIX architecture.
Oh, yea, there are differences is all UNIX/Linux systems at the system call level.... that is why folks who want cross-platform applications use the GCC compiler!! Yes, some UNIX/Linux versions have different feature sets.... kinda like a dictionary... lots of words to choose from but most people just use a few of them (words)......
The greater question is 'what is your application environment and what do you want do accomplish?'