Linux assembly comiled successfully

.datamsg:.string "hello,world!\n"len=.-msg.text.global _start_start:movl $len,%edxmovl $msg,%ecxmovl $1,%ebxmovl $4,%eaxint $0x80movl $0,%ebxmovl $1,%eaxint $0x80

as -o hello.o hello.s

as may only compile source file but not linked!

ld -s -o hello hello.o

./hello

hello,world!