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Shell creates a user to generate a random password script

Source: Internet
Author: User
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Method for creating random numbers

1 ~~~~

/Dev/urandom

In Linux, a device/dev/urandom is used to generate a random number sequence. With this device, we can generate random strings as needed.

For example, if we want to generate a random password with 8-digit letters and numbers, we can:
[Linux @ test/tmp] $ cat/dev/urandom | head-1 | md5sum | head-c 8
6baf9282

2 ~~~~

In fact, linux already provides a system environment variable.

 
 
    
  
  
  1. [chengmo@centos5 shell]$ echo $RANDOM 
    2. 
  
  
  2. 66918 
    3. 
  
  
  3. [chengmo@centos5 shell]$ echo $RANDOM 
    4. 
  
  
  4. 10092 
    5.

I may have doubts. How can I obtain a random number with more than five digits?

In the case of ten digits, use % to get the remainder of 10.

 
 
    
  
  
  1. echo $((RANDOM%10)) 
    2.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~

Vi passwd. sh

# Create a 10-digit random password...

 
 
    
  
  
  1. #!/bin/bash 
    2. 
  
  
  2. a=(a b c d e A B C D E F @ $ % ^ 0 1 2 3 4 5 6 7 8 9) 
    3. 
  
  
    4. 
  
  
  4. for ((i=0;i<10;i++));do 
    5. 
  
  
    6. 
  
  
  6.  echo -n ${a[$RANDOM % ${#a[@]}]} 
    7. 
  
  
    8. 
  
  
  8. done 
    9. 
  
  
    10. 
  
  
  10. echo 
    11.

Run the script:

[Root @ 2 shell] # sh passwd. sh
BF8366c @ 13

Vi useradd. sh

# Create five accounts and reference random passwords.

 
 
    
  
  
  1. #!/bin/bash 
    2. 
  
  
  2. i=1
    3. 
  
  
  3. while [ $i -le 5 ] 
    4. 
  
  
  4. do 
    5. 
  
  
  5.  useradd red$i 
    6. 
  
  
  6. a=`sh ./passwd.sh` 
    7. 
  
  
  7.  echo " red$i:$a " >> sumuserpasswd
    8. 
  
  
  8.  echo "~~~~~~~~~~~" >> sumuserpasswd 
    9. 
  
  
  9.  echo red$i:$a|chpasswd 
    10. 
  
  
  10. # echo $a | passwd –-stdin red"$i"
    11. 
  
  
  11.  let i++ 
    12. 
  
  
  12. done 
    13.

Run sh useradd. sh.

[Root @ 2 shell] # cat/etc/passwd | grep red
Red1: x: 515: 515:/home/red1:/bin/bash
Red2: x: 516: 516:/home/red2:/bin/bash
Red3: x: 517: 517:/home/red3:/bin/bash
Red4: x: 518: 518:/home/red4:/bin/bash
Red5: x: 519: 519:/home/red5:/bin/bash

# View results
[Root @ 2 shell] #Cat sumuserpasswd
Red1: $ Ca7 % 298d2
~~~~~~~~~~~~~
Red2: eEaBBB7Fb4
~~~~~~~~~~~~~
Red3: % 3e1_cece
~~~~~~~~~~~~~
Red4: 3 @ F % @ B0584
~~~~~~~~~~~~~
Red5: AdEe ^ 6BF $ F

# Test
[Root @ 2 shell] # su red1
[Red1 @ 2 shell] $ su red2
Password:
[Red2 @ 2 shell] $

You can also use html to display our results:

Html table code

 
 
    
  
  
  1. <body>
    2. 
  
  
  2. <tableborder='1'>
    3. 
  
  
  3. <tr>
    4. 
  
  
  4. <td>user</td>
    5. 
  
  
  5. <td>passwd</td>
    6. 
  
  
  6. </tr>
    7. 
  
  
  7. <tr>
    8. 
  
  
  8. <td>test1</td>
    9. 
  
  
  9. <td>123123</td>
    10. 
  
  
  10. </tr>
    11. 
  
  
  11. <tr>
    12. 
  
  
  12. <td>test2</td>
    13. 
  
  
  13. <td>aaabbb</td>
    14. 
  
  
  14. </tr>
    15. 
  
  
  15. </table>
    16. 
  
  
  16. </body>
    17.

You can direct your account and password to the webpage in html syntax.

 
 
    
  
  
  1. Tempw.index.html
    2. 
  
  
  2. Echo "
    3. 
   
  3. Echo "<tableborder = \" 1 \ ">"> $ TEMP
    4.  
  4. Echo "<tr> <td> username </td> <td> password </td> </tr> $ TEMP
    5.  
  5. Echo "<tr> <td> $ I </td> <td> $ a </td> </tr>"> $ TEMP
    6.  
  6. Echo "</table> </body> 
    7.  
  7. Echo "open index.html"
    8.



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