Shell高级编程企业实战题参考解答
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目录：
企业面试题1：监控MySQL主从同步是否异常，如果异常，则发送短信或者邮件给管理员。提示：如果没主从同步环境,可以用下面文本放到文件里读取来模拟：
阶段1：开发一个守护进程脚本每30秒实现检测一次。
阶段2：如果同步出现如下错误号（1158,1159,1008,1007,1062），则跳过错误。
阶段3：请使用数组技术实现上述脚本（获取主从判断及错误号部分）
模拟文本
[root@oldboy~]# mysql -uroot-p‘oldboy‘ -S /data/3307/mysql.sock -e "show slavestatus\G;"
*************************** 1.row ***************************
Slave_IO_State:Waiting formaster to send event
Master_Host:10.0.0.179 #当前的mysql master服务器主机
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File:mysql-bin.000013
Read_Master_Log_Pos: 502547
Relay_Log_File:relay-bin.000013
Relay_Log_Pos:251
Relay_Master_Log_File:mysql-bin.000013
Slave_IO_Running:Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB: mysql
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 502547
Relay_Log_Space:502986
Until_Condition:None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0 #和主库比同步延迟的秒数，这个参数很重要
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
脚本
[root@shell scripts]# vicheck_mysql_slave.sh
#!/bin/sh
#oldboy linux training
#2015-05-17
#说明：本脚本来自老男孩linux21期学员张耀开发！
# Source function library.
. /etc/init.d/functions
# Defined variables
MysqlUser=root
MysqlPass=oldboy123
MysqlPort=3307
Mysqlsock=/data/$MysqlPort/mysql.sock
ErrorNo=(1158 1159 1008 10071062)
errorlog=/tmp/error_skip.log
MysqlCmd="/application/mysql/bin/mysql-u$MysqlUser -p$MysqlPass -S $Mysqlsock"
# Judge mysql server is ok?
[ -S $Mysqlsock ] ||{
echo "Maybe MySQL have sometingwrong"
exit 1
}
# Defined skip error Functions
function error_skip(){
local flag
flag=0
for num in ${ErrorNo[@]}
do
if [ "$1" == "$num"];then
$MysqlCmd -e‘stop slave;set globalsql_slave_skip_counter=1;start slave;‘
echo "$(date +%F_%R) $1">>$errorlog
else
echo "$(date +%F_%R) $1">>$errorlog
((flag++))
fi
done
[ "$flag" =="${#ErrorNo[@]}" ] &&{
action "MySQL Slave"/bin/false
uniq $errorlog|mail -s "MySQLSlave is error" 12345678@qq.com
}
}
# Defined check slave Functions
function check_slave(){
MyResult=`$MysqlCmd -e‘show slavestatus\G‘|egrep ‘_Running|Behind_Master|SQL_Errno‘ |awk ‘{print $NF}‘`
array=($MyResult)
if [ "${array[0]}" =="Yes" -a "${array[1]}" == "Yes" -a"${array[2]}" == "0" ]
then
action "MySQL Slave"/bin/true
else
error_skip ${array[3]}
fi
}
# Defined main Functions
function main(){
while true
do
check_slave
sleep 60
done
}
main
企业面试题2：使用for循环在/oldboy目录下通过随机小写10个字母，批量创建10个html文件，名称例如为：
[root@oldboy oldboy]# sh/server/scripts/oldboy.sh
[root@oldboy oldboy]# ls -l
total 0
-rw-r--r-- 1 root root 0 Apr 1511:34 coaolvajcq_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 gmkhrancxh_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 jdxexendbe_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 qcawgsrtkp_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 qnvuxvicni_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 tmdjormaxr_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 ugaywanjlm_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 vfrphtqjpc_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 vioesjmcbu_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 wzewnojiwe_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1511:34 xzzruhdzda_oldboy.html
请用至少两种方法实现，将以上文件名中的oldboy全部改成oldgirl(用for循环实现),并且html改成大写。
2.1批量创建脚本
[root@shell scripts]# vitouch2.sh
#!/bin/bash
Path=/oldboy
[ -d $Path ] || mkdir $Path
for i in `seq 10`
do
char=`echo $RANDOM|md5sum|cut -c 2-11|tr[0-9] [a-j]`
touch $Path/${char}_oldboy.html
done
[root@shell scripts]# shtouch2.sh
[root@shell scripts]# ll -h/oldboy/
total 0
-rw-r--r-- 1 root root 0 Apr 1107:49 aeddbiacdj_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 bccbacghba_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 bdhijefefb_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 bhfghjcgaa_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 ddaacedijc_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 ebcbbfabaf_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 ecafccebbi_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 egcdafafad_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 iehfcgfaef_oldboy.html
-rw-r--r-- 1 root root 0 Apr 1107:49 ifddfaaicd_oldboy.html
2.2批量改名
[root@shell scripts]# vimv2.sh
#!/bin/bash
Path=/oldboy
[ -d $Path ] && cd $Path
for file in `ls`
do
mv $file `echo $file|sed -e"s#oldboy#oldgirl#g" -e "s#html#HTML#g" `
done
[root@shell scripts]# sh mv2.sh
[root@shell scripts]# ll -h/oldboy/
total 0
-rw-r--r-- 1 root root 0 Apr 1107:49 aeddbiacdj_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 bccbacghba_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 bdhijefefb_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 bhfghjcgaa_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 ddaacedijc_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 ebcbbfabaf_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 ecafccebbi_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 egcdafafad_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 iehfcgfaef_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1107:49 ifddfaaicd_oldgirl.HTML
[root@shell scripts]# vimv3.sh
#!/bin/bash
Path=/oldboy
[ -d $Path ] && cd $Path
for file in `ls`
do
mv $file `echo${file/oldboy.html/oldgirl.HTML}`
done
[root@shell scripts]# sh mv3.sh
[root@shell scripts]# ll -h/oldboy/
total 0
-rw-r--r-- 1 root root 0 Apr 1108:12 abcaeacdbe_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 affabgbccg_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 badbifffbg_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 ccbcifibbe_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 cchbacgegb_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 cdfbjfdiib_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 chjechdgab_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 ghibcfcbee_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 icafaafbdb_oldgirl.HTML
-rw-r--r-- 1 root root 0 Apr 1108:12 igiijhbebj_oldgirl.HTML企业面试题3：批量创建10个系统帐号oldboy01-oldboy10并设置密码（密码为随机8位字符串）。
[root@shell scripts]# viuseradd.sh #! /bin/bash . /etc/init.d/functions Path=/server/scripts UserDb=$Path/user.db FailDb=$Path/fail_user.db [ -d "$Path" ] || mkdir-p $Path [ -f "$UserDb" ] ||touch $UserDb [ -f "$FailDb" ] ||touch $FailDb for n in $(seq -w 10) do passwd=`echo $(date+%t%N)$RANDOM|md5sum|cut -c 2-9` useradd oldboy$n >&/dev/null&& user_status=$? echo "$passwd"|passwd --stdinoldboy$n >&/dev/null && pass_status=$? if [ $user_status -eq 0 -a $pass_status -eq0 ];then action "adduser oldboy$n"/bin/true echo -e "user:\toldboy$npass:$passwd" >>$UserDb else action "adduser oldboy$n"/bin/false echo -e "user:\toldboy$npass:$passwd" >>$FailDb fi done [root@shell scripts]# shuseradd.sh adduser oldboy01 [ OK ] adduser oldboy02 [ OK ] adduser oldboy03 [ OK ] adduser oldboy04 [ OK ] adduser oldboy05 [ OK ] adduser oldboy06 [ OK ] adduser oldboy07 [ OK ] adduser oldboy08 [ OK ] adduser oldboy09 [ OK ] adduser oldboy10 [ OK ] [root@shell scripts]# cat user.db user: oldboy01 pass:f3291720 user: oldboy02 pass:457a9f30 user: oldboy03 pass:ff186389 user: oldboy04 pass:8f884b7c user: oldboy05 pass:26f831b4 user: oldboy06 pass:344e2300 user: oldboy07 pass:0736b278 user: oldboy08 pass:67c1fa76 user: oldboy09 pass:b11e7aa9 user: oldboy10 pass:9e0c3673
企业面试题4：写一个脚本，实现判断10.0.0.0/24网络里，当前在线用户的IP有哪些（方法有很多）
#!/bin/sh for n in `seq 254` do ping -c1 10.0.0.$n &>/dev/null if [ $? -eq 0 ] then echo "10.0.0.$n is up ">>/tmp/uplist.log else echo "10.0.0.$n is down ">>/tmp/downlist.log fi done
企业实战题5：请用至少两种方法实现！写一个脚本解决DOS攻击生产案例。
提示：根据web日志或者或者网络连接数，监控当某个IP并发连接数或者短时内PV达到100，即调用防火墙命令封掉对应的IP，监控频率每隔3分钟。防火墙命令为：iptables-AINPUT -s 10.0.1.10 -j DROP。
[root@shell scripts]# vi dos.sh
#!/bin/bash
log=/tmp/tmp.log
[ -f $log ] || touch $log
function add_iptables(){
whileread line
do
ip=`echo $line|awk ‘{print $2}‘`
count=`echo $line|awk ‘{print $1}‘`
if [ $count -gt 100 ] && [`iptables -L -n|grep "$ip"|wc -l` -lt 1 ]
then
iptables -I INPUT -s $ip -jDROP
echo "$line isdropped" >>/tmp/droplist.log
fi
done<$log
}
function main(){
whiletrue
do
#awk ‘{print $1}‘ access.log|grep-v "^$"|sort|uniq -c >$log
netstat -an|grep EST|awk -F ‘[:]+‘ ‘{print $6}‘|sort|uniq -c >$log
add_iptables
sleep 180
done
}
main企业实战题6：开发mysql多实例启动脚本：
已知mysql多实例启动命令为：mysqld_safe--defaults-file=/data/3306/my.cnf&
停止命令为：mysqladmin -u root -poldboy123 -S /data/3306/mysql.sockshutdown
请完成mysql多实例启动启动脚本的编写
要求：用函数，case语句、if语句等实现。
[root@shell scripts]# vi mysqld1.sh
#!/bin/bash
# chkconfig: 2345 65 37
# description: manager multiplemysqld server.
# Warning: This script uses the/etc/init.d/functions system function.
# System kernel version isCentOS6.6,2.6.32-504.el6.x86_64.
# I‘m not sure whether other systemscan be used normally.
# Source function library.
. /etc/init.d/functions
Port=$2
datadir=/data/$2
Path="/application/mysql"
CmdPath="$Path/bin"
MysqlCmd="$CmdPath/mysqld_safe"
prog=mysqld
Port=$2
datadir=/data/$2
pidfile=${PIDFILE-$datadir/mysqld.pid}
lockfile=${LOCKFILE-/var/lock/subsys/mysqld$Port}
MysqlConf="$datadir/my.cnf"
RETVAL=0
Usage1(){
echo -e "\033[33m USAGE: $0 {startport|stop port|status port|restart port} \033[0m"
exit 6
}
Usage2(){
echo -e "\033[33m MySQL DaemonProgram Need Configuration File,like $datadir/my.cnf \033[0m"
exit 6
}
[ -n "$Port" -a -z "`echo"${Port//[0-9]/}"`" ] || Usage1
start(){
[ -x $MysqlCmd ] || exit 5
[ -f $MysqlConf ] || Usage2
echo -n $"Starting $prog: "
daemon --pidfile=${pidfile}"$MysqlCmd --defaults-file=$MysqlConf &>/dev/null &"
sleep 1
RETVAL=$?
echo
[ $RETVAL = 0 ] && touch${lockfile}
return $RETVAL
}
stop(){
echo -n $"Stopping $prog: "
killproc -p $pidfile
retval=$?
echo
[ $retval -eq 0 ] && rm -f${lockfile}
return $retval
}
restart() {
stop
sleep 1
start
}
rh_status() {
status -p $pidfile
}
rh_status_q() {
rh_status >/dev/null 2>&1
}
case "$1" in
start)
rh_status_q && exit 0
$1
;;
stop)
rh_status_q || exit 0
$1
;;
restart)
$1
;;
status)
rh_status
;;
*)
Usage1
exit 2
esac企业实战题7:如何实现对MySQL数据库进行分库备份，请用脚本实现
[root@shell scripts]# vifenku_backup.sh
#!/bin/bash
MysqlUser=root
PassWord=oldboy123
Port=3306
Socket="/data/$Port/mysql.sock"
MysqlCmd="mysql -u$MysqlUser-p$PassWord -S $Socket"
Database=`$MysqlCmd -e "showdatabases;"|egrep -v "Database|_schema|mysql"`
MysqlDump="mysqldump-u$MysqlUser -p$PassWord -S $Socket"
IP=`ifconfig eth0|awk -F "[:]+" ‘NR==2 {print $4}‘`
BackupDir=/backup/$IP
[ -d $BackupDir ] || mkdir -p$BackupDir
for dbname in $Database
do
$MysqlDump --events -B $dbname|gzip>/$BackupDir/${dbname}_$(date +%F)_bak.sql.gz
done
[root@shell 10.0.0.3]# ls
chongtu_2015-04-11_bak.sql.gz oldboy_2015-04-11_bak.sql.gz test_2015-04-11_bak.sql.gz
mysql_2015-04-11_bak.sql.gz qqqqqq_2015-04-11_bak.sql.gz企业实战题8:如何实现对MySQL数据库进行分库加分表备份，请用脚本实现
[root@shell scripts]# vifenbiao_backup.sh
#!/bin/bash
MysqlUser=root
PassWord=oldboy123
Port=3306
Socket="/data/$Port/mysql.sock"
MysqlCmd="mysql -u$MysqlUser-p$PassWord -S $Socket"
Database=`$MysqlCmd -e "showdatabases;"|egrep -v "Database|_schema|mysql"`
MysqlDump="mysqldump-u$MysqlUser -p$PassWord -S $Socket"
IP=`ifconfig eth0|awk -F "[:]+" ‘NR==2 {print $4}‘`
BackupDir=/backup/$IP
[ -d $BackupDir ] || mkdir -p$BackupDir
for dbname in $Database
do
[ ! -d /$BackupDir/$dbname ] &&mkdir -p /$BackupDir/$dbname
TABLE=`$MysqlCmd -e "show tables from$dbname;"|sed ‘1d‘`
for table in $TABLE
do
$MysqlDump $dbname $table|gzip>/$BackupDir/$dbname/${dbname}_${table}_$(date +%F).sql.gz
done
done企业面试题9： bash for循环打印下面这句话中字母数不大于6的单词(昆仑万维面试题)。
Iam oldboy teacher welcome to oldboy training class.
请用至少两种方法实现！
[root@shell scripts]# vi length.sh
#!/bin/bash
echo "-------wc -L----"
for word in I am oldboy teacherwelcome to oldboy training class.
do
if [ `echo ${word}|wc -L` -le 6 ]
then
echo $word
fi
done
echo"-----{#word}-----"
for word in I am oldboy teacherwelcome to oldboy training class.
do
if [ ${#word} -le 6 ]
then
echo $word
fi
done
echo "-----exprlength-----"
for word in I am oldboy teacherwelcome to oldboy training class.
do
if [ `expr length "$word"` -le 6]
then
echo $word
fi
done
echo"-----{word:0:6}-----"
for word in I am oldboy teacherwelcome to oldboy training class.
do
if [ "$word" =="${word:0:6}" ]
then
echo $word
fi
done
echo "-----awk-----"
echo "I am oldboy teacherwelcome to oldboy training class"|awk ‘{for(i=1;i<=NF;i++)if(length($i)<=6)print $i}‘
echo "-----awk2-----"
echo -n "I am oldboy teacherwelcome to oldboy training class." | awk ‘BEGIN {RS=FS} length($0)<=6{print $0}‘
echo "-----数组-----"
arr=(I am oldboy teacher welcometo oldboy training class.)
for word in ${arr[@]}
do
if [ ${#word} -le 6 ]
then
echo $word
fi
done
echo-----------------------------
for((i=0;i<${#arr[*]};i++))
do
if [ ${#arr[$i]} -le 6 ]
then
echo ${arr[$i]}
fi
done
[root@shell scripts]# shlength.sh
-------wc -L----
I
am
oldboy
to
oldboy
class.
-----{#word}-----
I
am
oldboy
to
oldboy
class.
-----expr length-----
I
am
oldboy
to
oldboy
class.
-----{word:0:6}-----
I
am
oldboy
to
oldboy
class.
-----awk-----
I
am
oldboy
to
oldboy
class
-----awk2-----
I
am
oldboy
to
oldboy
class.
-----数组-----
I
am
oldboy
to
oldboy
class.
-----------------------------
I
am
oldboy
to
oldboy
class.想从0开始成为这样的SHELL高手么？请猛戳：
原文地址：http://oldboy.blog.51cto.com/2561410/1665163
