8个实用的Shell脚本分享

几个Shell脚本的例子，觉得还不错。
【例子:001】判断输入为数字，字符或其他
复制代码代码如下:
#！/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！ " ;;
[a-zA-Z]） echo -e "Good job, Your input is a character！ " ;;
       *） echo -e "Your input is wrong, input again！   " ;;
esac

【例子:002】求平均数
复制代码代码如下:
#！/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
复制代码代码如下:
[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
复制代码代码如下:
# 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
复制代码代码如下:
[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
复制代码代码如下:
[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 date=" $（date）
    fi
    mkdir -p /tmp/temp
    cat < testfile > "/tmp/temp/myfile.$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
复制代码代码如下:
[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
复制代码代码如下:
[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
复制代码代码如下:
#！/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..."