man 命令格式化指定的手册页面集合。如果为 Section 参数指定一个段,那么 man 命令在手册页面的该段中搜索 Title 参数指定的标题。Section 参数的值可以是 1 到 8 的阿拉伯数字或字母。
Section 数字是:
1 表示用户命令和守护进程。
2 表示系统调用和内核服务。
3 表示函数或者函数库。
4 表示特殊文件、设备驱动程序和硬件。
5 表示配置文件。
6 表示游戏。
7 表示杂项命令。
8 表示管理命令和守护进程。
9 表示和内核相关的文件
此时使用whatis命令,参考whatis命令,
1 2 3 4 5 6
$ whatis read read (1) - bash built-in commands, see bash(1) read (1p) - read a line from standard input read (2) - read from a file descriptor read (3p) - read from a file read (n) - Read from a channel
READ(2) Linux Programmer's Manual READ(2) NAME read - read from a file descriptor SYNOPSIS #include <unistd.h> ssize_t read(int fd, void *buf, size_t count); DESCRIPTION read() attempts to read up to count bytes from file descriptor fd into the buffer starting at buf. On files that support seeking, the read operation commences at the current file offset, and the file offset is incremented by the number of bytes read. If the current file offset is at or past the end of file, no bytes are read, and read() returns zero. If count is zero, read() may detect the errors described below. In the absence of any errors, or if read() does not check for errors, a read() with a count of 0 returns zero and has no other effects. If count is greater than SSIZE_MAX, the result is unspecified.