sh-3.00# ls
main.c
sh-3.00# gcc main.c -o hello_world
sh-3.00# ls
hello_world  main.c
sh-3.00# ./hello_world
Hello World!
sh-3.00# cat main.c
int main()
{
        printf ("Hello World!\n");
        return 0;
}
sh-3.00#