I have come across this term used by a lot of companies which post their vacancies that the candidate must be " proficient programming c on unix". What does that imply .... I mean i program on c using visual studio and i suppose the syntax rules dont change if i use any other OS. I know that the compilation is a bit different on the linux platform like using the gcc command for compilation and all that stuff. Is there any other difference which is implied by this term ????????