unix基础知识

1.unix体系结构

2.登录

登录口令存放在/etc/passwd文件中，冒号分割成7部分，规格如下：

the login name, encrypted password, numeric user ID(205), numeric group ID (105),

a comment field, home directory (/home/sar), and shell program (/bin/ksh).

我的centos的passwd文件内容如下

3.文件和目录

 使用stat或者fstat查看文件信息

 注意：文件名中不能出现“/”和null

The only two characters that cannot appear in a filename are the slash character (/) and the null character.

The slash separates the filenames that form a pathname (described next) and the null character terminates a pathname.