利用shell实现批量添加用户

批量添加用户并设置随机密码，把添加的用户的名字和密码保存到文件中。

[root@lamp scripts]# cat user.sh 
#!/bin/sh

for i in `seq -w 10`
do
  pass=$(echo "`date`$RANDOM"|md5sum|cut -c 1-8)         //取随机数的方法是date结果和random随机数拼接并计算md5值取前8位
  useradd kg$i
  echo "$pass"|passwd --stdin kg$i
  echo -e "kg$i	$pass">>/tmp/pass.txt
done
[root@lamp scripts]# seq -w 10
01
02
03
04
05
06
07
08
09
10
[root@lamp scripts]# sh user.sh 
Changing password for user kg01.
passwd: all authentication tokens updated successfully.
Changing password for user kg02.
passwd: all authentication tokens updated successfully.
Changing password for user kg03.
passwd: all authentication tokens updated successfully.
Changing password for user kg04.
passwd: all authentication tokens updated successfully.
Changing password for user kg05.
passwd: all authentication tokens updated successfully.
Changing password for user kg06.
passwd: all authentication tokens updated successfully.
Changing password for user kg07.
passwd: all authentication tokens updated successfully.
Changing password for user kg08.
passwd: all authentication tokens updated successfully.
Changing password for user kg09.
passwd: all authentication tokens updated successfully.
Changing password for user kg10.
passwd: all authentication tokens updated successfully.
[root@lamp scripts]# cat /tmp/pass.txt 
kg01    3577b000
kg02    3ddefcfe
kg03    c1ec8c1e
kg04    0bdcdafc
kg05    f172c380
kg06    99471166
kg07    fbe82aeb
kg08    cad21c1c
kg09    5f7cdc56
kg10    b60958ad
[root@lamp scripts]# tail -10 /etc/passwd
kg01:x:504:504::/home/kg01:/bin/bash
kg02:x:505:505::/home/kg02:/bin/bash
kg03:x:506:506::/home/kg03:/bin/bash
kg04:x:507:507::/home/kg04:/bin/bash
kg05:x:508:508::/home/kg05:/bin/bash
kg06:x:509:509::/home/kg06:/bin/bash
kg07:x:510:510::/home/kg07:/bin/bash
kg08:x:511:511::/home/kg08:/bin/bash
kg09:x:512:512::/home/kg09:/bin/bash
kg10:x:513:513::/home/kg10:/bin/bash
[root@lamp scripts]# 

linux中取随机数的几种方法：

[root@lamp scripts]# echo $RANDOM
10474
[root@lamp scripts]# openssl rand -base64 8
C8ZBCmMhlKc=
[root@lamp scripts]# openssl rand -base64 6
BSaZWw8v
[root@lamp scripts]# openssl rand -base64 3
+S4K
[root@lamp scripts]# openssl rand -base64 4
daNeuw==
[root@lamp scripts]# date +%s%N
1448293383949936583
[root@lamp scripts]# date +%s%N
1448293385095579398
[root@lamp scripts]# date +%s%N
1448293386596694243
[root@lamp scripts]# head /dev/urandom|cksum
1336286598 1963
[root@lamp scripts]# head /dev/urandom|cksum
3913907857 2588
[root@lamp scripts]# head /dev/urandom|cksum
321627736 1498
[root@lamp scripts]# cat /proc/sys/kernel/random/uuid 
b8238fed-be13-47ac-8e30-b86ea0f822ff
[root@lamp scripts]# cat /proc/sys/kernel/random/uuid 
0bb0cb5d-157e-45f9-889a-0d6a93d3d328
[root@lamp scripts]# cat /proc/sys/kernel/random/uuid 
526c2cb3-a335-4013-bf71-108e7517c4d9
[root@lamp scripts]#