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 " " " "|sed -r 's#(.*)#useradd 1 ; pass=$((RANDOM+10000000)); echo "$pass"|passwd --stdin 1; echo -e "1 `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 ' ' ' ' | 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 ' ' ' '|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.