Ever imagined of using C as a scripting language? Install TCC. Write a simple C program:

// add.c
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char** argv)
{
   /* No error checking. */
   int a = atoi(argv[1]);
   int b = atoi(argv[2]);
   printf("%d\n", (a + b));
   return 0;
}

Add this line to the top of the file:

#!tcc -run

Mark the file as executable:

$ chmod +x add.c

Run it:

$ ./add.c 10 20
30

The TCC executable is only 100Kb in size, but it can compile the Linux kernel! An ideal use for TCC is as an embedded compiler to dynamically generate executables.