Build these executables typing
    make

All programs have a software breakpoint (int3) at the very beginning.
Then you can debug each of them with:

    gdbtui -ex run ./ex01.runme
   
Then single-step typing `si` once and pressing ENTER. Pressing ENTER
yet another time repeats the last command (in this case, step into).
As soon as you encounter 4 consecuvite NOP instructions you have reached
the end of the code (just before calling sys_exit(42)).

To enjoy gdbtui's beauty, you should create ~/.gdbinit with this config:

    layout asm
    layout regs
    set disassembly-flavor intel

    winheight REGS -10
    winheight CMD -5
    winheight ASM +15

    refresh