macbug@one:~/code/asm$ nasm -f elf hw.asm
macbug@one:~/code/asm$ ls -s -o hw hw.o
4 -rwxrwxr-x 1 macbug  50 jan 31 22:05 hw
4 -rw-rw-r-- 1 macbug 624 jan 31 22:09 hw.o
macbug@one:~/code/asm$ hw
Hello, world!
macbug@one:~/code/asm$