shell 编程例子—第9章源码

shell 编程例子—第9章源码

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#!/bin/bash
#this is a example
cd /root/txtfile/
echo "----------------" >> bac_ztg.txt
date >> bac_ztg.txt
cat ztg* >> bac_ztg.txt
echo "" >> bac_ztg.txt



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#!/bin/bash
#this is a example for break
echo 请在命令后输入一个数字n,然后会得到1+2+...+n之和
if [ $# -ne 1 ]
then
    echo 请输入并且仅输入一个数字
    exit 1
fi
TOTAL=0
VAR=$1
while true
do
    TOTAL=$[TOTAL+VAR]
    VAR=$[VAR-1]
    if [ $VAR -eq 0 ]
    then
        break
    fi
done
echo $TOTAL



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#!/bin/bash
#this is a example for case
cd /root/txtfile
echo please give your choice to display a file:
echo "1) display ztg1.txt"
echo "2) display ztg2.txt"

echo enter your choice:
read var

case $var in
    1) cat ztg1.txt;;
    2) cat ztg2.txt;;
    *) echo wrong;;
esac



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#!/bin/bash
#this is a example for continue
echo 请在命令后输入一个数字n,然后会得到1-n之间奇数之和
if [ $# -ne 1 ]
then
    echo 请输入并且仅输入一个数字
    exit 1
fi
TOTAL=0
VAR=$1
while true
do
    if [ $VAR -eq 0 ]
    then
        break
    elif [ $[VAR%2] -eq 0 ]
    then
        VAR=$[VAR-1]
        continue
    elif true
    then
        TOTAL=$[TOTAL+VAR]
        VAR=$[VAR-1]
    fi
done
echo $TOTAL



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#!/bin/bash
#this is a example for for
for num in 1 2 3 4 5 6
do
    echo $num的平方:
    expr $num \* $num
#   { echo $num的平方:;expr $num \* $num;}
done



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#!/bin/bash
#this is a example for function
display()
{
    if [ $# -ne 1 ]
    then
        echo 请在命令后输入一个文件名或目录名
        exit 1
    fi
    if [ -d $1 ]
    then
        dir $1
    elif [ -f $1 ]
    then
        cat $1
    elif true
    then
        echo 没有该文件名或目录名
    fi
    echo 请在命令后输入一个文件名或目录名
}
display $1




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#!/bin/bash
#this is a example for if
cd /root/txtfile/
if [ -f ztg1.txt ]
then
    echo ztg1.txt is a file:
    cat ztg1.txt
elif [ -d /root/txtfile ]
then
    echo in /root/txtfile is:
    dir /root/txtfile
fi



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#!/bin/bash
#this is a example for shift
if [ $# -eq 0 ]
then
    echo no number!
    exit 1
fi

TOTAL=0

until [ $# -qe 0 ]
do
    TOTAL=expr $TOTAL + $1
    shift
done

echo $TOTAL


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#!/bin/bash
#this is a example for shift_add
if [ $# -eq 0 ]
then
    echo no number!
    exit 1
fi
export TOTAL=0
until [ $# -eq 0 ]
do
    TOTAL=$[TOTAL+$1]
    shift
done
echo $TOTAL



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#!/bin/bash
#this is a example for until
cd /root/txtfile
echo 请输入文件名:
read FNAME
echo 请输入文件内容,输入end!退出:
read VAR
until [ $VAR = end! ]
do
    echo $VAR >> $FNAME
    echo 请输入文件内容,输入end!退出:
    read VAR
done



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#!/bin/bash
#this is a example for while
echo "请输入数字(大于等于100将退出):"
read VAR
while [ $VAR -lt 100 ]
do
    echo $VAR的平方:
    expr $VAR \* $VAR
#   { echo $VAR的平方:;expr $VAR \* $VAR;}
    echo "请输入数字(大于等于100将退出):"
    read VAR
done



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