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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