简单shell脚本练习
1、编写脚本/root/bin/systeminfo.sh,显示当前主机系统信息，包括主机名，IPv4地址，操作系统版本，内核版本，CPU型号，内存大小，硬盘大小。#!/bin/bash
echo Hostname: `hostname`
echo IP address: `ifconfig|egrep -o "[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}"|head -n1`
echo System version: `cat /etc/system-release`
echo kernel version: `uname -r`
echo CPU type : `lscpu |grep 'Model name'|sed 's/.*://'|sed 's/^[[:space:]]\+//'`
echo Disk size :`fdisk -l|grep "sda:"|sed 's/.*://'|sed 's/,.*//'|sed 's/^[[:space:]]\+//'`
echo Memory size : `free -m|grep "Mem"|tr -s [[:space:]]|cut -d" " -f2` MB
运行结果
# bash systeminfo.sh
Hostname: shao
IP address: 10.1.53.2
System version: CentOS Linux release 7.2.1511 (Core)
kernel version: 3.10.0-327.el7.x86_64
CPU type : Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz
Disk size :214.7 GB
Memory size : 1824 MB
2、编写脚本/root/bin/backup.sh，可实现每日将/etc/目录备份到/root/etcYYYY-mm-dd中
#!/bin/bash
cp -arv /etc /root/etc`date +%F`
3、编写脚本/root/bin/disk.sh,显示当前硬盘分区中空间利用率最大的值
#!/bin/bash
echo "The max using rate is:`df |grep "/dev/sd"| cut -c 44-46 | sort -nr | head -1`%"
运行结果
# bash disk.sh
The max using rate is: 74%
4、编写脚本/root/bin/links.sh,显示正连接本主机的每个远程主机的IPv4地址和连接数，并按连接数从大到小排序
#!/bin/bash
echo "the links number is:"
netstat -nt |tr -s ' '|cut -d ' ' -f5 |cut -d: -f1 |grep |sort |uniq -c|sort -nr
运行结果
# bash links.sh
the links number is:
2 10.1.53.3
5、写一个脚本/root/bin/sumid.sh，计算/etc/passwd文件中的第10个用户和第20用户的ID之和
#!/bin/bash
echo 'The sum is'
id1=`cat /etc/passwd | sed -n '10p' | cut -d: -f3`
id2=`cat /etc/passwd | sed -n '20p' | cut -d: -f3`
let idsum=$id1+$id2
echo "The sum is:$idsum"
unset idsum
运行结果
# bash sumid.sh
The sum is:70
6、写一个脚本/root/bin/sumspace.sh，传递两个文件路径作为参数给脚本，计算这两个文件中所有空白行之和
#!/bin/bash
file1_blank=`grep "^[[:space:]]*$" $1 | wc -l`
file2_blank=`grep "^[[:space:]]*$" $2 | wc -l`
sumspace=$[$file1_blank+$file2_blank]
echo "The tatal blank line:$sumspace"
运行结果
# bash sumspace.sh /etc/passwd /etc/fstab
The tatal blank line:1
7、写一个脚本/root/bin/sumfile.sh,统计/etc, /var, /usr目录中共有多少个一级子目录和文件
#!/bin/bash
etcnum=`ls -d /etc/*|wc -l`
varnum=`ls -d /var/*|wc -l`
usrnum=`ls -d /usr/*|wc -l`
echo "the totalfile is $"
运行结果
# bash sumfile.sh
the totalfile is 298
8、写一个脚本/root/bin/argsnum.sh，接受一个文件路径作为参数；如果参数个数小于1，则提示用户“至少应该给一个参数”，并立即退出；如果参数个数不小于1，则显示第一个参数所指向的文件中的空白行数
#!/bin/bash
read -p "Enter a filename:" file
[ -z "$file" ] && echo "please enter a file name" && exit 2
echo -n "Theblank line number is:"
echo `grep -c'^[[:space:]]*$'$file`
运行结果
# bash sumspace.sh
Enter a filename:
please enter a file name
# bash sumspace.sh
Enter a filename:/etc/fstab
Theblank line number is:1
9、写一个脚本/root/bin/hostping.sh，接受一个主机的IPv4地址做为参数，测试是否可连通。如果能ping通，则提示用户“该IP地址可访问”；如果不可ping通，则提示用户“该IP地址不可访问”
#!/bin/bash
[ $# -ne 1 ] && echo "please input one ipaddr" && exit 2
ping -c1 -w1 $1 &> /dev/null && echo "ping successful" || echo "ping failed"
运行结果
# bash hostping.sh
please input one ipaddr
# bash hostping.sh 10.1.254.254
ping successful
10、判断硬盘的每个分区空间和inode的利用率是否大于80，如果是，发邮件通知root磁盘满
#!/bin/bash
mount=$((df;df -i) | grep "/dev/sd" | tr -s ' ' | cut -d' ' -f5 | grep -o "[[:digit:]]\+" | sort | tail -1)
[ "$mount" -ge 80 ] && echo "disk almost full" | mail -s "dangerous" root || exit 3
11、指定文件做为参数，判断文件是否为.sh后缀，如果是，添加x权限
#!/bin/bash
read -p "please input a test file: " FILENAME
[ ! -f $FILENAME ] && echo "please input a real file" && exit 100
echo $FILENAME | grep -q '.*\.sh$'&& (chmod +x $FILENAME ; echo "Add x right for the file successfully") || echo "this is not a .sh file"
运行结果
# ls
excute.shhostping.shper.shsumfile.sh
# bash excute.sh
please input a test file: hostping.sh
Add x right for the file successfully
12、判断输入的IP是否为合法IP
#!/bin/bash
read -p "please input one useful ip:" ip_addr
echo $ip_addr | grep -E "^(\.){3}\$" &> /dev/null&& echo "this is a useful ip" || echo "this is not a useful ip"
运行结果
# bash checkip.sh
please input one useful ip:10.1.534.1
this is not a useful ip
# bash checkip.sh
please input one useful ip:10.1.53.1
this is a useful ip
13、计算1+2+3+...+100
#!/bin/bash
#!/bin/bash
echo -e "\033[34m1-100 all positive integer's sum\033[0m : `echo {1..100} | tr " " "+" | bc`"
运行结果
# bash 100sum.sh
1-100 all positive integer's sum : 5050
方法二：seq -s + 1 100 | bc
14、输入起始值A和最后值B，计算从A+（A+1）...+(B-1)+B的总和
#!/bin/bash
read -p "first number:" a
read -p "second number:" b
[ $a -ge $b ] && echo "sum is `seq -s+ $b $a | bc`" || echo "sum is `seq -s+ $a $b | bc`"
运行结果
# bash sumAB.sh
first number:4
second number:8
sum is 30
# bash sumAB.sh
first number:100
second number:1
sum is 5050
15、chmod -rw /tmp/file1，编写脚本/root/bin/per.sh,判断当前用户对/tmp/file1文件 是否不可读且不可写
#!/bin/bash
[ -r /tmp/file1 -o-w /tmp/file1 ] && echo "`whoami` can read or write /tmp/file1" || echo"`whoami` can not read and can not write /tmp/file1"
运行结果
# bash per.sh
root can read or write /tmp/file1
16、编写脚本/root/bin/nologin.sh和login.sh,实现禁止和充许普通用户登录系统。
禁止
#!/bin/bash
[ -e /etc/nologin ] && echo "the normal user can not login already" ; exit || touch /etc/nologin
echo "disable normal user login "
允许
#!/bin/bash
[ -e /etc/nologin ] && rm -f /etc/nologin
echo "enable user login "
17、写一个脚本/root/bin/createuser.sh，实现如下功能： 使用一个用户名做为参数，如果指定参数的用户存在，就显 示其存在，否则添加之；显示添加的用户的id号等信息
#!/bin/bash
read -p "please input you name:" name
if cat /etc/passwd | cut -d: -f1 | grep -q "^$name$";then
echo "the username already exits"
else
useradd $name
cat /etc/passwd | grep "^$name\b"
fi
运行结果
# bash createuser.sh
please input you name:shao
the username already exits
# bash createuser.sh
please input you name:liu
liu:x:1014:1019::/home/liu:/bin/bash
18、写一个脚本/root/bin/yesorno.sh，提示用户输入yes或 no,并判断用户输入的是yes还是no,或是其它信息
#!/bin/bash
[ $# -ne 1 ] && echo "please input an arg" && exit
ans=`echo $1 | tr 'A-Z' 'a-z'`
if [ $ans = yes -o $ans = y ]
then
echo "yes"
elif [ $ans = n -o $ans = no ]
then
echo "no"
else
echo "error"
fi
运行结果
# bash yesorno.sh y
yes
# bash yesorno.sh
please input an arg
# bash yesorno.sh No
no
# bash yesorno.sh YES
yes
方法二
#!/bin/bash
read -p "Please input yes or no:" ans
case $ans in
|)
echo "The user input yes"
;;
|)
echo "The user input no"
;;
*)
echo "The user input other words"
esac
19、写一个脚本/root/bin/filetype.sh,判断用户输入文件路 径，显示其文件类型（普通，目录，链接，其它文件类型）
#!/bin/bash
read -p "please input a filename:" filename
! [ -e $filename ] && echo "The filename do not exist" && exit
if[ -h $filename ] ;then
echo "filetype issyslink file"
elif [ -d $filename ] ;then
echo "filetype is dirction"
elif [ -f $filename ] ;then
echo "filetype is common file"
else
echo "filetype is other"
fi
运行结果
# bash filetype.sh
please input a filename:/etc
filetype is dirction
# bash filetype.sh
please input a filename:/etc/redhhat-release
The filename do not exist
# bash filetype.sh
please input a filename:/etc/redhat-release
filetype issyslink file
# bash filetype.sh
please input a filename:/etc/issue
filetype is common file
20、写一个脚本/root/bin/checkint.sh,判断用户输入的参数是否为正整数
#!/bin/bash
[ $# -ne 1 ] && echo "Please input a number" && exit
if [[ $1 =~ ^0**$ ]]
then
echo "int"
else
echo "not int"
fi
运行结果
# bashcheckint.sh
Please input a number
# bashcheckint.sh 0
not int
# bashcheckint.sh 12
int
# bashcheckint.sh 1.1
not int
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