What happens when you type gcc main.c?

GCC is a compiler integrated for C and C++ and others programming languages, generate a binary executable program in the language of the machine where it is to run.

The acronym GCC stands for “GNU Compiler Collection”. and the Syntax is:

gcc [ option| file] …

Examples:

gcc hello.c: Compile the program in C hello.c, generate an executable file a.out.

gcc -o hello hello.c: compile the program in C hello.c, generate an executable file hello.

gcc -c hello.c:
it does not generate the executable, but the object code, in the file hello.o. If it does not indicate a name for the object file, use the name of the file in C and change the extension to .o.

gcc -c -o object.o hello.c:
generates the object code indicating the file name.

For more additional information use man gcc in Linux terminal.