几个Shell脚本的例子

【例子:001】判断输入为数字，字符或其他

#!/bin/bash
read -p "Enter a number or string here:" input 

case $input in
[0-9]) echo -e "Good job, Your input is a numberic! \n" ;;
[a-zA-Z]) echo -e "Good job, Your input is a character! \n" ;;
*) echo -e "Your input is wrong, input again! \n" ;;
esac 

【例子:002】求平均数

#!/bin/bash 

# Calculate the average of a series of numbers. 

SCORE="0"
AVERAGE="0"
SUM="0"
NUM="0" 

while true; do 

echo -n "Enter your score [0-100%] ('q' for quit): "; read SCORE; 

if (("$SCORE" < "0")) || (("$SCORE" > "100")); then
echo "Be serious. Common, try again: "
elif [ "$SCORE" == "q" ]; then
echo "Average rating: $AVERAGE%."
break
else
SUM=$[$SUM + $SCORE]
NUM=$[$NUM + 1]
AVERAGE=$[$SUM / $NUM]
fi 

done 

echo "Exiting." 

【例子:003】自减输出

[scriptname: doit.sh]
while (( $# > 0 ))
do
echo $*
shift
done 

/> ./doit.sh a b c d e
a b c d e
b c d e
c d e
d e
e 

【例子:004】在文件中添加前缀

# 人名列表
# cat namelist
Jame
Bob
Tom
Jerry
Sherry
Alice
John

# 脚本程序
# cat namelist.sh
#!/bin/bash
for name in $(cat namelist)
do
echo "name= " $name
done
echo "The name is out of namelist file"

# 输出结果
# ./namelist.sh
name= Jame
name= Bob
name= Tom
name= Jerry
name= Sherry
name= Alice
name= John
【例子:005】批量测试文件是否存在
[root@host ~]# cat testfile.sh
#!/bin/bash


for file in test*.sh
do
if [ -f $file ];then
echo "$file existed."
fi
done

[root@host ~]# ./testfile.sh
test.sh existed.
test1.sh existed.
test2.sh existed.
test3.sh existed.
test4.sh existed.
test5.sh existed.
test78.sh existed.
test_dev_null.sh existed.
testfile.sh existed.
【例子:005】用指定大小文件填充硬盘
[root@host ~]# df -ih /tmp
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/mapper/vg00-lvol5
1000K 3.8K 997K 1% /tmp
[root@host ~]# cat cover_disk.sh
#!/bin/env bash
counter=0
max=3800
remainder=0
while true
do
((counter=counter+1))
if [ ${#counter} -gt $max ];then
break
fi
((remainder=counter%1000))
if [ $remainder -eq 0 ];then
echo -e "counter=$counter\tdate=" $(date)
fi
mkdir -p /tmp/temp
cat < testfile > "/tmp/temp/myfile.$counter"
if [ $? -ne 0 ];then
echo "Failed to write file to Disk."
exit 1
fi
done
echo "Done!"
[root@host ~]# ./cover_disk.sh
counter=1000 date= Wed Sep 10 09:20:39 HKT 2014
counter=2000 date= Wed Sep 10 09:20:48 HKT 2014
counter=3000 date= Wed Sep 10 09:20:56 HKT 2014
cat: write error: No space left on device
Failed to write file to Disk.
dd if=/dev/zero of=testfile bs=1M count=1
【例子:006】通过遍历的方法读取配置文件
[root@host ~]# cat hosts.allow
127.0.0.1
127.0.0.2
127.0.0.3
127.0.0.4
127.0.0.5
127.0.0.6
127.0.0.7
127.0.0.8
127.0.0.9
[root@host ~]# cat readlines.sh
#!/bin/env bash
i=0
while read LINE;do
hosts_allow[$i]=$LINE
((i++))
done < hosts.allow
for ((i=1;i<=${#hosts_allow[@]};i++)); do
echo ${hosts_allow[$i]}
done
echo "Done"
[root@host ~]# ./readlines.sh
127.0.0.2
127.0.0.3
127.0.0.4
127.0.0.5
127.0.0.6
127.0.0.7
127.0.0.8
127.0.0.9
Done
【例子:007】简单正则表达式应用
[root@host ~]# cat regex.sh
#!/bin/env sh
#Filename: regex.sh
regex="[A-Za-z0-9]{6}"
if [[ $1 =~ $regex ]]
then
num=$1
echo $num
else
echo "Invalid entry"
exit 1
fi
[root@host ~]# ./regex.sh 123abc
123abc

#!/bin/env bash
#Filename: validint.sh
validint(){
ret=`echo $1 | awk '{start = match($1,/^-?[0-9]+$/);if (start == 0) print "1";else print "0"}'`
return $ret
}

validint $1

if [ $? -ne 0 ]; then
echo "Wrong Entry"
exit 1
else
echo "OK! Input number is:" $1
fi
【例子:008】简单的按日期备份文件
#!/bin/bash

NOW=$(date +"%m-%d-%Y") # 当前日期
FILE="backup.$NOW.tar.gz" # 备份文件
echo "Backing up data to /tmp/backup.$NOW.tar.gz file, please wait..." #打印信息
tar xcvf /tmp/backup.$NOW.tar.gz /home/ /etc/ /var # 同时备份多个文件到指定的tar压缩文件中
echo "Done..."

【例子:009】交互式环境select的使用
#!/bin/bash

echo "What is your favorite OS?"

select OS in "Windows" "Linux/Unix" "Mac OS" "Other"
do
break
done

echo "You have selected $OS"

root@localhost:~/training# ./select.sh
What is your favorite OS?
1) Windows
2) Linux/Unix
3) Mac OS
4) Other
#? 1
You have selected Windows
【例子:010】批量修改文件名的脚本
#!/bin/bash
# we have less than 3 arguments. Print the help text:
if [ $# -lt 3 ]; then
cat <<-EOF
ren -- renames a number of files using sed regular expressions
USAGE: ren.sh 'regexp' 'replacement' files
EXAMPLE: rename all *.HTM files in *.html:
ren 'HTM$' 'html' *.HTM
EOF
exit 0
fi
OLD="$1"
NEW="$2"
# The shift command removes one argument from the list of
# command line arguments.
shift
shift
# $* contains now all the files:
for file in $*
do
if [ -f "$file" ]; then
newfile=`echo "$file" | sed "s/${OLD}/${NEW}/g"`
if [ -f "$newfile" ]; then
echo "ERROR: $newfile exists already"
else
echo "renaming $file to $newfile "
mv "$file" "$newfile"
fi
fi
done
root@localhost:~/training# ./ren.sh "HTML$" "html" file*.HTML
renaming file10.HTML to file10.html
renaming file1.HTML to file1.html
renaming file2.HTML to file2.html
renaming file3.HTML to file3.html
renaming file4.HTML to file4.html
renaming file5.HTML to file5.html
renaming file6.HTML to file6.html
renaming file7.HTML to file7.html
renaming file8.HTML to file8.html
renaming file9.HTML to file9.html
【例子:011】break语句在脚本中的应用示例
#!/bin/bash

for VAR1 in 1 2 3
do
for VAR2 in 0 5
do
if [ $VAR1 -eq 2 -a $VAR2 -eq 0 ]
then
break 2 # 退出第二重循环，亦即退出整个循环
else
echo "第一个变量:$VAR1 第二个变量:$VAR2"
fi
done
done
root@localhost:~/training# ./test.sh
第一个变量:1 第二个变量:0
第一个变量:1 第二个变量:5

【例子:012】/dev/tty在读取人工输入中的特殊作用
#!/bin/bash
# 用来验证两次输入的密码是否一致

printf "Enter your passwd: " # 提示输入
stty -echo # 关闭自动打印输入字符的功能
read pwd1 < /dev/tty # 读取密码
printf "\nEnter again: " # 再次提示输入
read pwd2 < /dev/tty # 再读取一次以确认
stty echo # 打开自动打印输入字符的功能

if [[ "$pwd1" == "$pwd2" ]]; then # 对两次输入的密码进行判断
echo -e "\nPASSWORD: the same"
else
echo -e "\nPASSWORD: not same"
fi
root@localhost:~/training# ./test.sh
Enter your passwd:
Enter again:
PASSWORD: the same

【例子:013】/dev/null在脚本中的简单示例
#!/bin/bash

if grep /bin/bash $0 > /dev/null 2>&1 # 只关心命令的退出状态而不管其输出
then # 对退出状态进行判断
echo -e "/bin/bash in $0\n"
else
echo -e "/bin/bash not in $0\n"
fi
脚本输出:
root@localhost:~/training# ./test.sh
/bin/bash in ./test.sh

【例子:014】构建自己的bin目录存放执行脚本，然后随便执行的简单示例
$ cd # <span style="font-family:FangSong_GB2312;">进入家目录</span>
$ mkdir bin <span style="font-family:FangSong_GB2312;"># 创建$HOME目录下自己的bin目录</span>
$ mv test.sh bin # 将我们自己的脚本放到创建的bin目录下
<span style="font-family:FangSong_GB2312;">$ </span>PATH=$PATH:$HOME/bin # 将个人的bin目录放到PATH<span style="font-family:FangSong_GB2312;">中

$ test.sh # 现在就可以直接执行自己的脚本了</span>

【例子:015】将长句子中单词长度为5及以上的单词打印出来
#!/bin/bash
# filename: test.sh

sentence="When you're attracted to someone it just means that your subconscious is attracted to their subconscious, subconsciously.
So what we think of as fate, is just two neuroses knowing they're a perfect match."

for word in ${sentence}
do
new=`echo $word | tr -cd '[a-zA-Z]'` # 去除句子中的 ，或者'
len=${#new} # 求长度
if [ "$len" -ge 5 ] # 再判断
then
echo $new
fi
done
root@localhost:~# ./test.sh
youre
attracted
someone
means
subconscious
attracted
their
subconscious
subconsciously
think
neuroses
knowing
theyre
perfect
match
【例子:016】根据输入的数据(年4位，月2位)，来判断上个月天数
#!/bin/bash

get_last_day()
{
year=`expr substr $1 1 4`
month=`expr substr $1 5 2`
curr_month=`echo $month | tr -d '0'` # 去掉里面的0，方便后面计算
echo "curr_month=$curr_month"
last_month=`expr $curr_month - 1`
case $last_month in
01|03|05|07|08|10|12|0)
echo "上个月天数-->" 31 ;;
02)
if [ `expr $year % 400` = 0 ] ; then
echo "上个月天数-->" 29
elif [ `expr $year % 4` = 0 ] && [ `expr $year % 100` != 0 ] ; then
echo "上个月天数-->" 29
else
echo "上个月天数-->" 28
fi ;;
*)
echo "上个月天数-->" 30
esac
}

if [ $# -ne 1 ]; then
echo "Usage: $0 201608"
else
get_last_day $1
fi

root@localhost:~/training# ./test.sh 201601
上个月天数--> 31
【例子:017】统计文件中每个单词出现的频率
#!/bin/sh
# 从标准输入读取文件流，再输出出现频率的前n，默认:25个单词的列表
# 附上出现频率的计数，按照这个计数由大到小排列
# 输出到标准输出
# 语法: wf [n]

tr -cs A-Za-z\' '\n' |
tr A-Z a-z |
sort |
uniq -c |
sort -k1,1nr -k2 |
sed ${1:-25}q
root@localhost:~/training# wf 10 < /etc/hosts | pr -c4 -t -w80
6 ip 1 1 archive 1 capable
3 ff 1 allnodes 1 are 1 cn
2 localhost 1 allrouters
【例子:018】使用while和break等待用户登录
#!/bin/bash
# 等待特定用户登录，每30秒确认一次
# filename: wait_for_user_login.sh

read -p "Ener username:-> " user
while true
do
if who | grep "$user" > /dev/null
then
echo "The $user now logged in."
break
else
sleep 30
fi
done
root@localhost:~/shell# ./wait_for_user_login.sh
Ener username:-> guest
The guest now logged in.
【例子:019】结合while,case,break,shift做简单的选项处理
#!/bin/bash

# 将标志变量设置为空值
file= verbose= quiet= long=

while [ $# -gt 0 ] # 执行循环直到没有参数为止
do
case $1 in # 检查第一个参数
-f) file=$2
shift ;; # 移位-f，使得结尾shift得到$2的值
-v) verbose=true
quiet= ;;
-q) quiet=true
verbose= ;;
-l) long=true ;;
--) shift
break ;;
-*) echo "$0: $1: unrecongnized option >&2" ;;
*) break ;;
esac
done
~
【例子:020】read读取多个变量处理，及文本遍历的两种常用方式
#!/bin/bash

while IFS=: read user pwd pid gid fullname homedir shell # IFS作为列之间的分隔符号，read读取多个变量
do
printf "The user=%s homedir=%s\n" "$user" "$homedir" # 对文本中的行进行处理
done < /etc/passwd # 读取文件

# 第二种方式
#!/bin/bash

cat /etc/passwd |
while IFS=: read user pwd pid gid fullname homedir shell
do
printf "The user=%s homedir=%s\n" "$user" "$homedir"
done
【例子:021】复制目录树的两个简单脚本
#!/bin/bash
# 方式一
find /root/shell -type d -print | # 寻找所有目录
sed 's;/root/shell/;/tmp/shell/;' | # 更改名称，使用;作为定界符
sed 's/^/mkdir -p /' | # 插入mkdir -p 命令
sh -x # 以Shell的跟踪模式执行

# 方式二
find /root/shell -type d -print | # 寻找所有目录
sed 's;/root/shell/;/tmp/shell/;' | # 更改名称，使用;作为定界符
while read newdir # 读取新的目录名
do
mkdir -p $newdir
done
~
【例子:022】发邮件给系统前10名磁盘用户，要求清理磁盘空间
#!/bin/bash

cd /home # 移动到目录的顶端
du -s * | # 产生原始磁盘用量
sort -nr | # 以数字排序，最高的在第一位
sed 10q | # 在前10行之后就停止
while read amount name # 将读取的数据分别作为amount, name变量
do
mail -s "disk usage warning" $name << EOF
Gretings. You are one of the top 10 consumers of disk space
on the system. Your home directory users $amount disk blocks.

Please clean up unneeded files, as soon as possible.

Thanks,
Your friendly neighborhood system administrator.
EOF
done
【例子:023】将密码文件转换为Shell邮寄列表
#!/bin/bash

# passwd-to-mailing-list
#
# 产生使用特定shell的所有用户邮寄列表
#
# 语法: passwd-to-mailing-list < /etc/passwd

# 删除临时性文件
rm -rf /tmp/*.mailing-list

# 从标准输入中读取
while IFS=: read user passwd uid gid name home Shell
do
Shell=${Shell:-/bin/sh} # 如为空shell,指/bin/sh
file="/tmp/$(echo $Shell | sed -e 's;^/;;' -e 's;/;-;g').mailing-list"
echo $user, >> $file
done
root@localhost:~# vim passwd-to-mailing-list
root@localhost:~# passwd-to-mailing-list < /etc/passwd
root@localhost:~# cat /tmp/bin-bash.mailing-list
root,
test,
user,
root@localhost:~# cat /tmp/bin-sh.mailing-list
libuuid,
jerry,
【例子:024】变更目录时更新PS1
#!/bin/bash

cd()
{
command cd "$@" # 实际改变目录
x=$(pwd) # 取得当前目录的名称,传递给变量
PS1="${x##*/}\$ " # 截断前面的组成部分，指定给PS1
}
root$ # 最后输出，类似于这种，看不到目录的完整路径
【例子:025】根据XML文件中的license时间来判断是否过期
<?xml version="1.0" encoding="gb2312"?>
<license>
<pos>中国,福建,福州市,鼓楼区</pos>
<installid>123123</installid>
<device>hdsas_base_3.0.0.2_16Q2_RC2</device>
<id>_RC257971fe611f0</id>
<hwid>f04c3d1eb4bf6113</hwid>
<issuetime>2016-08-02 16:46:39</issuetime>
<expired>30 days</expired>
</license>


获得<issuetime>2016-08-02 16:46:39</issuetime>时间加上<expired>30 days</expired>
期限，得到时间减去系统当前时间，小于7天，显示license即将在几天后过期。
代码如下:
#!/bin/bash

CURR_TIME=$(date +'%Y%m%d')
FILE_TIME=$(grep 'issuetime' hdlicense.xml | tr -d '[\-a-z<>/]' | awk '{print $1}')
REAL_TIME=$(date -d "$FILE_TIME +30 days" +%Y%m%d)

d1=$(date "+%s" -d "$REAL_TIME")
d2=$(date "+%s" -d "$CURR_TIME")

EXPI_TIME=$(((d1-d2)/86400))

if [ "$EXPI_TIME" -lt "7" ]; then
echo "你的license将在 $EXPI_TIME 天后过期!"
fi
【例子:026】根据参数来判断是否要新创建目录
#!/bin/bash

DIR=$1

if [ X"$DIR" = X"" ]; then
echo "Usage: `basename $0` directory to create" >&2
exit 1
fi

if [ -d $DIR ];then
echo "The directory you create is exist."
exit 0
else
echo "The $DIR does not exist, will create now."
echo -n "Create it now? [y/n]"
read ANS
if [ X"$ANS" = X"y" -o X"$ANS" = X"Y" ];then
mkdir $DIR > /dev/null 2>&1
if [ $? !=0 ]; then
echo "Error creating the direcory $DIR" >&2
exit 1
else
echo "Create $DIR OK"
exit 0
fi
fi
fi
【例子:027】创建新目录，并将当前目录下的所有.txt文件拷贝到新目录中
#!/bin/bash

DIR=testdir
THERE=`pwd`

mkdir $DIR > /dev/null 2>&1

if [ -d $DIR ]; then
cd $DIR
if [ $? = 0 ]; then
HERE=`pwd`
cp $THERE/*.txt $HERE
else
echo "Cannot cd to $DIR"
exit 1
fi
else
echo "Cannot create directory $THERE"
exit 1
fi
【例子:028】菜单显示小脚本
#!/bin/bash

USER=`whoami`
HOST=`hostname -s`
DATE=`date '+%d/%m/%Y'`

help(){
cat <<EOF
-----------------------------------------------------
User: $USER Host: $HOST Date: $DATE
-----------------------------------------------------
1. List files in current directory
2. Use the vi editor
3. See who is on the system
H. Help screen
Q. Exit Menu
-----------------------------------------------------
Your Choice [1, 2, 3, 4, H, Q] >
EOF
}

while :
do
help
echo -n "Enter your choice: "
read ANS
case $ANS in
1) ls -lart ;;
2) vi ;;
3) who ;;
H) help ;;
Q) exit 0 ;;
esac
done
【例子:029】判断输入是否为纯字母示例
#!/bin/bash
error_info()
{
echo "$@ error, please check your input."
exit 1
}

check_name()
{
NAME=`echo $1 | tr -d '[a-zA-Z]'`
if [ X"$NAME" = X"" ];then
return 0
else
return 1
fi
}

while :
do
echo -n "Please Input your first name:"
read F_NAME
if check_name $F_NAME; then
echo "Your First Name met the condition."
break
else
echo "Wrong input, please enter again."
fi
done


while :
do
echo -n "Please Input your last name:"
read L_NAME
if check_name $L_NAME; then
echo "Your Last Name met the condition."
break
else
error_info
fi
done
~