出现问题：

$nasm -f elf hello.asm -o hello.o

$ld -s hello.o -o hello

　　ld: i386 architecture of input file `hello.o' is incompatible with i386:x86-64 output

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尝试：

$ ld -m32 -s hello.o -o hello
　　ld: unrecognised emulation mode: 32
　　Supported emulations: elf_x86_64 elf32_x86_64 elf_i386 i386linux elf_l1om elf_k1om i386pep i386pe

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解决：

$nasm -f elf hello.asm -o hello.o

$ld -m elf_i386 -s hello.o -o hello

$./hello

　　Hello, world!