问题
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- What does the number in parentheses shown after Unix command names in manpages mean? 7 answers
For example, when I run man ioctl the page says IOCTL(2) at the top. What does that mean? Is there an IOCTL(1)? And how does one navigate between these?
回答1:
It's the man page section. From memory, section 1 is user programs, 2 is system calls, and 3 is standard C library calls, and 5 is file formats.
Wikipedia has the full explanation here.
回答2:
That's the man page section number. For example
man printf
(should) Give you section 1, printf the bash command, while
man 3 printf
gives you the C function printf.
来源：https://stackoverflow.com/questions/587676/why-do-programs-in-unix-like-environments-have-numbers-after-their-name