APUE第六章

口令文件

其实我觉得叫密码文件也可以&＃xff0c;

strptime&＃xff0c;strftime完成字符串和struct tm { day&＃xff0c; month&＃xff0c; year等等}的转换

finger 命令&＃xff0c;需要安装

阴影口令

阴影口令&＃xff0c;其实就是存储用户名和密码加密信息的文件

查看文件:

sudo cat /etc/shadow
root:$6$drbtofiPuQIhvTu3$Z6OjGV0Pbdn2AUUsxeyfCKRVpDYCQaSNGpKZQ3Qbv6DASW36J.2IWazgsrJVtk0R5efvnoSPbMhNZHk8WpIos1:18866:0:99999:7:::
daemon:*:18375:0:99999:7:::
bin:*:18375:0:99999:7:::
sys:*:18375:0:99999:7:::


组文件

查看 /etc/group&＃xff0c;adm那一行&＃xff0c;就有多个用户syslog和ubuntu

ubuntu&＃64;ubun2004:/etc$ cat /etc/group
root:x:0:
daemon:x:1:
bin:x:2:
sys:x:3:
adm:x:4:syslog,ubuntu
tty:x:5:


附属组ID

一个用户会参与多个项目&＃xff0c;从而属于多个组&＃xff0c;因此有附属组的概念&＃xff0c;

last utmp/wtmp 查询最近用户登录时间


ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ last wtmpwtmp begins Thu Apr 23 14:41:14 2020
ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ who utmp
ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ last utmpwtmp begins Thu Apr 23 14:41:14 2020
ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ vim /var/log/wtmp
ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ cat /var/log/wtmp
~~~reboot5.4.0-26-genericJ&＃xfffd;^&＃xfffd;&＃xfffd;:0ubuntu:0&＃xfffd;&＃xfffd;^&＃xfffd;&＃xfffd;5~~~runlevel5.4.0-26-generic&＃xfffd;&＃xfffd;^[a~~~shutdown5.4.0-26-genericx&＃xfffd;^*|~~~reboot5.4.0-26-generic~&＃xfffd;^&＃xfffd;&＃xfffd;5~~~runlevel5.4.0-26-generic&＃xfffd;&＃xfffd;^F&＃xfffd;pts/0ts/0ubuntu192.168.1.1&＃xfffd;&＃xfffd;^Qa&＃xfffd;pts/0&＃xfffd;&＃xfffd;^¡~~~shutdown5.4.0-26-generic&＃xfffd;&＃xfffd;^8v~~~reboot5.4.0-26-generic&＃xfffd;&＃xfffd;^X&＃xfffd;5~~~runlevel5.4.0-26-generic&＃xfffd;&＃xfffd;^;
pts/0ts/0ubuntu192.168.1.1&＃xfffd;&＃xfffd;^&＃xfffd;&＃xfffd;
&＃xfffd;&＃xfffd;
~~~shutdown5.4.0-26-generic&＃xfffd;&＃xfffd;^&＃xfffd;~~~reboot5.4.0-26-genericj&＃xfffd;^/5~~~runlevel5.4.0-26-generic&＃xfffd;&＃xfffd;^&＃xfffd;ALpts/0ts/0ubuntu192.168.1.1&＃xfffd;&＃xfffd;^&＃xfffd;8&＃xfffd;Lpts/0&＃xfffd;&＃xfffd;^9~~~shutdown5.4.0-26-gG:0ubuntu:0&＃xfffd;Z&＃xfffd;&＃96;&＃xfffd;&＃xfffd;~~~reboot5.8.0-59-generic&＃xfffd;(&＃xfffd;&＃96;-&＃xfffd;5~~~runlevel5.8.0-59-generic&＃xfffd;(~~~reboot5.8.0-59-generic&＃xfffd;&＃xfffd;&＃xfffd;&＃96;&＃xfffd;}5~~~runlevel5.8.0-59-genericƕ&＃xfffd;&＃96;&&＃xfffd;&＃xfffd;:0ubuntu:0Ε&＃xfffd;&＃96;Y&＃xfffd;~~~reboot5.8.0-63-generic&＃xfffd;&＃xfffd;ae!
5~~~runlevel5.8.0-63-generic&＃xfffd;&＃xfffd;
&＃xfffd;:0ubuntu:0&＃xfffd;&＃xfffd; a&＃xfffd;wa&＃xfffd;l~~~shutdown5.8.0-63-generic&＃xfffd;Oa&＃xfffd;~~~reboot5.11.0-25-generic&＃xfffd;Oa&＃xfffd;&＃xfffd;5~~~runlevel5.11.0-25-generic&＃xfffd;Oa&＃xfffd;&&＃xfffd;:0ubuntu:0&＃xfffd;OaL&＃xfffd;~~~reboot5.11.0-25-genericaH"5~~~runlevel5.11.0-25-generica&＃xfffd;_&＃xfffd;:0ubuntu:00au&~~~shutdown5.11.0-25-genericLK$a&＃96;&＃xfffd;~~~reboot5.11.0-27-generi&＃xfffd;(a/Z 5~~~runlevel5.11.0-27-generic&＃xfffd;(aX&＃xfffd;&＃xfffd;:0ubuntu:0F&＃xfffd;(aw&＃xfffd;~~~reboot5.11.0-27-generic&＃xfffd;1;aw&＃xfffd;5~~~runlevel5.11.0-27-generic&＃xfffd;1;a&＃xfffd;&＃xfffd;:0ubuntu:0&＃xfffd;1;an&＃xfffd;~~~reboot5.11.0-34-generic&＃xfffd;LEa&＃xfffd;%5~~~runlevel5.11.0-34-generic&＃xfffd;LEa&＃xfffd;a
ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ cat /var/run/utmp
~~~reboot5.11.0-34-generic&＃xfffd;LEa&＃xfffd;%5~~~runlevel5.11.0-34-generic&＃xfffd;LEa&＃xfffd;a


uname查询操作系统信息:

ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ uname -a
Linux ubun2004 5.11.0-34-generic #36~20.04.1-Ubuntu SMP Fri Aug 27 08:06:32 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux


hostname用来查询主机在TCP/IP上的网络地址

我的主机名是ubun2004&＃xff0c;地址127.0.0.1&＃xff0c;原因可能是因为我是虚拟机

ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ hostname -a
ubun2004
ubuntu&＃64;ubun2004:~/work/xv6-labs-2020$ hostname -i
127.0.1.1

查看 etc内的文件:

 以我的阿里云主机为例

[root&＃64;haohaoxuexi ~]# cat /etc/hosts
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
127.0.0.1 localhost localhost
172.24.48.63 haohaoxuexi haohaoxuexi
103.224.251.67 www.bt.cn[root&＃64;haohaoxuexi etc]# cat /etc/shadow
root:$6$yqGz78F4Ij/R$QXP5xZFmg5U0P09lh4V/SWSeJrD//2CkZHhFn9jSEsw8AC7NGQyaUO8LuDfOybxHWh0Srpa0DPEdJkw/ZZGj//:18783:0:99999:7:::
bin:*:17834:0:99999:7:::
daemon:*:17834:0:99999:7:::
adm:*:17834:0:99999:7:::
lp:*:17834:0:99999:7:::
sync:*:17834:0:99999:7:::
shutdown:*:17834:0:99999:7:::
halt:*:17834:0:99999:7:::
mail:*:17834:0:99999:7:::[root&＃64;haohaoxuexi etc]# cat /etc/networks
default 0.0.0.0
loopback 127.0.0.0
link-local 169.254.0.0

其中/etc/networks文件为符号链接&＃xff0c;直接连接到 /etc/inet/networks, 不过我查了自己的虚拟机和阿里云&＃xff0c;并没有inet这个目录