Shell Exercises (12)

Exercise 1:Detect file Changes

Requirements: There are two Linux servers A and B, if a can ssh directly to B, do not enter the password. A and B have a directory called/data/web/. Here are a lot of files, of course, we do not know the specific number of subdirectories, if the previous A and B files in this directory are identical. But now I'm not sure if it's the same. Solid needs us to write a script to implement such a function, detection of a machine and B machine/data/web/directory of the similarities and differences, we use a machine on the document as standard. For example, if the B machine is missing a a.txt file, then we should be able to detect it, or B machine on the B.txt file has changed, we should be able to detect (b machine More files We do not consider).

Tip: Use the core command md5sum A.txt to figure out the MD5 value and compare it to the B machine.

Reference Answer:

#!/bin/bash# date:2018 March 15 dir=/data/webb_ip=192.168.139.128find  $dir  -type f |xargs  md5sum > /tmp/md5.txtssh  $B _ip  "find  $dir  -type f |xargs  md5sum > /tmp/md5_b.txt "scp  $B _ip:/tmp/md5_b.txt /tmpfor f in  ' awk   ' {print $2} '  /tmp/md5.txt ' do    if grep -q  "$f"  /tmp/ Md5_b.txt    then        md5_a= ' grep  $f   /tmp/md5.txt|awk  ' {print $1} '         md5_b= ' grep  $f  /tmp/md5_b.txt|awk  ' {print $1} '         if [   $MD 5_a !=  $MD 5_b ]        then             echo  "$f  changed ..."          fi    else        echo  "$f  deleted ..."     fidone

Exercise 2: determine if 80 ports are turned on

Requirement: write a script to determine if the Web service is open on your Linux server? (Listen to port 80) if it is turned on, please determine what the service is running, is it httpd or nginx or something else?

reference answer:

#!/bin/bash# date:2018 year March 15 port= ' netstat -lnp|grep -w  80 ' if [ -z  "$port  ];then    echo " not service  Start! "     exit;fiweb_service= ' echo  $port |awk -f  '/'   ' {print $2} ' |awk  -F  ': '   ' {print $1} ' case  $web _service in    httpd)          echo  "Apache server."         ;;     nginx)         echo  "Nginx server."         ;;     *)         echo  "Other server."         ;; Esac 

Exercise 3: monitoring MySQL Services

requirements: Assuming that the current MySQL service has a root password of 123456, the script detects that the MySQL service is normal (for example, it can go to MySQL to perform show processlist) and detects if the current MySQL service is master or slave, If it is from, please determine if its master-slave service is abnormal. If it's the Lord, you don't need to do anything.

reference answer:

#!/bin/bash# date:2018 March 15 login= "mysql -uroot -p123456" $login  -e  "show  Processlist " >/tmp/mysql_error.log 2>&1if [ $? -ne 0 ]then     echo  "mysql server something wrong!"     exit;else     $login  -e  "Show slave status\g"  > /tmp/mysql_slave_status.log    res= ' Wc -l /tmp/mysql_slave_ status.log| awk  ' {print $1} '     if [  $res  -gt 0 ]     then        y1=grep  "slave_io_running:"  /tmp/mysql_slave_status.log |awk  ' {print $2} '          y2=grep  "slave_sql_running:"  /tmp/mysql_slave_status.log |awk  ' {print $2} '         if [  "$y 1"  ==  "yes"  ] && [  "$y 2"  ==  "yes"  ]         then            echo  "Slave status good!"         else             echo  "slave down!"         fi    fifi

Exercise 4: user script with options

Requirements:

1 only three options ' –del ' –add ' help input other options error.

2 The use of ' –add ' requires verifying that the user name exists and that the feedback exists. And not added. Does not exist then create the user, cut > Add the same password as the user name. and feedback.

3 The use of ' –del ' requires verifying that the user name exists and that the user and his or her home directory are deleted. Does not exist then feedback that the user does not save > in.

4–HELP option feedback out how to use

5 support to, separate delete multiple or add multiple users at once.

6 can use echo $? Detect script execution successfully deleted or added as 0, error messages are other numbers.

7 can with, divide.  Add or remove multiple users at once. For example Adddel.sh–add user1,user2,user3 ....

8 No obvious bugs are allowed.

reference answer:

#!/bin/bash# date:2018 March 15 If [ $# -eq 0 -o $# -gt 2 ]then     echo  "usage $0 --add username or $0 --del  Username or $0 --help. "     exit 1ficase $1 in    --add)          for u in  ' echo $2|sed  ' s/,/ /g '          do            if  awk -F  ': '   ' {print $1} '  /etc/passwd|grep -qw  ' $u '              then                 echo  "the user  $u  is exist."             else     & nbsp;          useradd  $u                  echo -e  $u "$u \n$u" |passwd   > /dev/null 2>&1                 echo  "the user  $u  added successfully."             fi         done        ;;     --del)         for u in  ' echo  $2|sed -r  ' s/,/ /g '         do             if awk -F  ': '   ' {print $1} '  /etc/passwd|grep -qw  "$u"             then                 userdel -r  $u                  echo -e  "the user  $u  deleted successfully."             else                 echo  "the user  $u  not  exist. "             fi         done        ;;     --HELP)         echo -e  "--add  Can add user,and the passwd is the same as username.\nit can  add multiuser such as --add user1,user2,user3 "        echo -e "--del cat delete  user. It can delete user such as --del user1,user2,user3 ... "         ;;     *)         echo  "Usage $0 --add  username or $0 --del username or $0 --help. "         exit 1        ;; Esac

Shell Exercises (12)