1. System Administration HW3 - Shell Script chenyp

2. Computer Center, CS, NCTU 2 Requirements  File statistics (20%+10%) use one-line command to show files statistics Bonus(10%)  script (20%) Write a shell script to parse log.  A simple search platform (60%)

3. Computer Center, CS, NCTU 3 File statistics  Use one-line command to show File statistics.  Print the sum of files’ size in the directory, find the largest and the smallest files, and print its filenames, filesizes and owners. (not include subdirectories)  All commands should be concatenated using "|"(pipe) in one line.  Can not create temporary file.  If the number of the largest or the smallest is more than one, choose the last one.  No “&&” “||” “>” “>>” “<“.

4. Computer Center, CS, NCTU 4 File statistics  Examples:  % ls –l  -rw-r--r-- 1 chenyp gcs 720 Nov 14 18:25 test  -rw-r--r-- 1 chenyp gcs 720 Nov 14 16:55 test_a  -rw-r--r-- 1 chenyp gcs 378 Nov 10 17:12 test_b  -rw-r--r-- 1 chenyp gcs 397 Nov 13 16:59 test_c  -rw-r--r-- 1 chenyp gcs 536 Nov 12 17:43 test_d  -rw-r--r-- 1 chenyp gcs 191 Nov 14 17:25 test_e  %./hw3_1.sh  Bonus(10%) If you can do it with subdirectories, you will get extra 10%. 2222 Max: test_a 720 chenyp Min: test_e 191 chenyp

5. Computer Center, CS, NCTU 5 script  Write a script to parse log for ssh bruteforce.  Print the IP address and times descending.  Syntax Parserlog.sh [-n number] –f file -n  Show the most Nth times and its ip address.  If n is none, show all and sorted by times descending. -f  Log file  Sample file: –http://nasa.cs.nctu.edu.tw/logfile

6. Computer Center, CS, NCTU 6 script  SSH bruteforce Only parse these three formats Nov 15 13:53:32 NASA sshd[12397]: Invalid user supporte from 84.73.134.84 Nov 15 13:53:35 NASA sshd[12399]: Invalid user soporte from 84.73.134.84 Nov 15 21:45:25 NASA sshd[16601]: error: PAM: authentication error for root from 122.229.6.189 Nov 15 22:00:36 NASA sshd[16765]: error: PAM: authentication error for root from 115.186.131.106 Nov 15 22:16:40 NASA sshd[16868]: error: PAM: authentication error for root from 67.206.169.146 Nov 15 22:31:59 NASA sshd[16964]: error: PAM: authentication error for root from 74.238.205.245 Nov 15 22:47:22 NASA sshd[17129]: error: PAM: authentication error for root from 70.247.71.201 Nov 15 16:28:15 bsd1 sshd[6587]: error: PAM: authentication error for illegal user onlyeric23 from 140.113.246.1  Example % Parserlog.sh –n 3 –f /tmp/logfile 70.247.71.201 7 times 82.207.96.161 6 times 208.124.238.246 5 times 115.186.131.106 5 times 140.113.47.207 5 times 95.155.122.12 5 times

7. Computer Center, CS, NCTU 7 A simple search platform  Write a user-friendly search platform by using dialog(1)  First, you should show a welcome message.

8. Computer Center, CS, NCTU 8 A simple search platform  Second, you should use menubox for client to choose which service to provide.

9. Computer Center, CS, NCTU 9 A simple search platform  Basic search: Input a keyword. Go to the wiki and show the first introduction for the keyword.

10. Computer Center, CS, NCTU 10 A simple search platform  Advanced search: Input a keyword. Show the content for the keyword and use checklist to choose which information to display.

11. Computer Center, CS, NCTU 11 A simple search platform  Mergedata Input a keyword. Show the content for the keyword and use checklist to choose which information to merge. You should merge files to the wikimerge/keyword.tar.bz2 The keyword.tar.bz2 contains the files client chosen. Java.tar.bz2 contains  geography.txt  history.txt  Notes.txt  Externel_links.txt

12. Computer Center, CS, NCTU 12 A simple search platform  Show mergedata First, you should display which files in the wikimerge/ and use menubox for client to choose. And show all the content in the keyword.tar.bz2. Example:  You should display the content of the –geography.txt –history.txt –Notes.txt –Externel_links.txt  If you choose the java.tar.bz2.

13. Computer Center, CS, NCTU 13 Help  IRC channel #nctuNASA on freenode  Newsgroup cs.course.sysadmin  BBS bs2.to board CS-SysAdmin  Email ta@nasa.cs.nctu.edu.tw  Goto CSCC to ask professional 3F!