批量创建10个用户stu01-stu10，创建10stu01-stu10

批量创建10个用户stu01-stu10，创建10stu01-stu10

1.批量创建10个用户stu01-stu10,并且设置随机8位密码，要求不能用shell循环(例如：for,while等)，只能用命令及管道实现。

 1 ##方法1：
 2 [root@server tmp]# echo stu{01..10}|tr " " "\n"|sed -r 's#(.*)#useradd \1 ; pass=$((RANDOM+10000000)); echo "$pass"|passwd --stdin \1; echo -e "\1 \t `echo "$pass"`">>/tmp/oldboy.log#g'|bash
 3 useradd: user 'stu01' already exists
 4 Changing password for user stu01.
 5 passwd: all authentication tokens updated successfully.
 6 useradd: user 'stu02' already exists
 7 Changing password for user stu02.
 8 passwd: all authentication tokens updated successfully.
 9 useradd: user 'stu03' already exists
10 Changing password for user stu03.
11 passwd: all authentication tokens updated successfully.
12 useradd: user 'stu04' already exists
13 Changing password for user stu04.
14 passwd: all authentication tokens updated successfully.
15 useradd: user 'stu05' already exists
16 Changing password for user stu05.
17 passwd: all authentication tokens updated successfully.
18 useradd: user 'stu06' already exists
19 Changing password for user stu06.
20 passwd: all authentication tokens updated successfully.
21 useradd: user 'stu07' already exists
22 Changing password for user stu07.
23 passwd: all authentication tokens updated successfully.
24 useradd: user 'stu08' already exists
25 Changing password for user stu08.
26 passwd: all authentication tokens updated successfully.
27 useradd: user 'stu09' already exists
28 Changing password for user stu09.
29 passwd: all authentication tokens updated successfully.
30 useradd: user 'stu10' already exists
31 Changing password for user stu10.
32 passwd: all authentication tokens updated successfully.
33 上述命令实际就是再拼N条下面的命令的组合，举一条命令stu01用户的过程拆解如下：
34 useradd stu01 ; 
35 pass=$((RANDOM+10000000)); 
36 echo "$pass"|passwd --stdin stu01; 
37 echo -e "stu01        `echo "$pass"`">>/tmp/oldboy.log
38 特别说明：如果用shell循环结构会更简单，之所以限制使用循环的目的是锻炼学生的基础命令运用
39 能力，学到现在还没学到SHELL循环课程呢
40 ##方法2：
41 [root@server tmp]# echo stu{11..12}|xargs -n1 useradd ;echo stu{11..12}:`cat /dev/urandom|tr -dc 0-9|fold -w8|head -1`|xargs -n1|tee -a pass.txt|chpasswd
42 ##方法3：
43 [root@server tmp]# echo stu{21..30} | tr ' ' '\n' | sed -e 's/^/useradd /' -e 's/\(stu[0-9]\{2\}\)$/\1 \&\& echo "\1:`echo $[$RANDOM**3] | cut -c1-8`" | tee -a userInfo.txt | cut -d: -f2 | passwd --stdin \1/' | bash
44 Changing password for user stu21.
45 passwd: all authentication tokens updated successfully.
46 Changing password for user stu22.
47 passwd: all authentication tokens updated successfully.
48 Changing password for user stu23.
49 passwd: all authentication tokens updated successfully.
50 Changing password for user stu24.
51 passwd: all authentication tokens updated successfully.
52 Changing password for user stu25.
53 passwd: all authentication tokens updated successfully.
54 Changing password for user stu26.
55 passwd: all authentication tokens updated successfully.
56 Changing password for user stu27.
57 passwd: all authentication tokens updated successfully.
58 Changing password for user stu28.
59 passwd: all authentication tokens updated successfully.
60 Changing password for user stu29.
61 passwd: all authentication tokens updated successfully.
62 Changing password for user stu30.
63 passwd: all authentication tokens updated successfully.
64 功能: 创建10个用户 分别是 stu21-stu30 其密码是用随机数变量RANDOM生成，均保存至 userInfo.txt中，格式: username:passwd   这个写的不算好  如果有更好的一定要分享哦！  上面的随机数 我之前是用日期生成的，是不对的，因为有可能会有重复现象，所以我后来干脆用RANDOM**3取其前8位，可确保唯一性
65 ##方法4：
66 [root@server tmp]# echo stu{01..10} |tr ' ' '\n'|sed -rn 's@^(.*)$@useradd \1 ; echo $RANDOM|md5sum|cut -c 1-8 >/data/\1;cat /data/\1|passwd --stdin \1@gp'|bash
67 useradd: user 'stu01' already exists
68 Changing password for user stu01.
69 passwd: all authentication tokens updated successfully.
70 useradd: user 'stu02' already exists
71 Changing password for user stu02.
72 passwd: all authentication tokens updated successfully.
73 useradd: user 'stu03' already exists
74 Changing password for user stu03.
75 passwd: all authentication tokens updated successfully.
76 useradd: user 'stu04' already exists
77 Changing password for user stu04.
78 passwd: all authentication tokens updated successfully.
79 useradd: user 'stu05' already exists
80 Changing password for user stu05.
81 passwd: all authentication tokens updated successfully.
82 useradd: user 'stu06' already exists
83 Changing password for user stu06.
84 passwd: all authentication tokens updated successfully.
85 useradd: user 'stu07' already exists
86 Changing password for user stu07.
87 passwd: all authentication tokens updated successfully.
88 useradd: user 'stu08' already exists
89 Changing password for user stu08.
90 passwd: all authentication tokens updated successfully.
91 useradd: user 'stu09' already exists
92 Changing password for user stu09.
93 passwd: all authentication tokens updated successfully.
94 useradd: user 'stu10' already exists
95 Changing password for user stu10.
96 passwd: all authentication tokens updated successfully.