Solaris

Hi friends,
I was wondering if UNIX programs really care about file extensions like Microsoft Windows applications do. Because I think an extension doesn't really change the nature of a file, or does it? But when I try to compile the c source code file named "hello", gcc gives me error, saying that hello is not a known file type. Any comments!

UNIX doesn't when it comes to executing files. It checks the first few bytes of a file to figure out what type it is.

The behavior of other things depends on the program in question. gcc does care. When compiling a .c, it knows it's a C file. .cpp, it knows it's a C++ file. .f, might be fortran. (gcc's not just C -- it's the GNU compiler collection.) And so forth.

Things like makefiles also depend on file extensions -- when something depends on file.o, it knows it needs to gcc -c file.c or file.cpp to get it without having to be told to use file.c explicitly, which is very convenient.