shell腳本編程實例--進度條，求和&平均值，斐波那契，改變字符串大小順序

利用求1+2+3+…+100的和，要求打印出1+2+3+…+100=5050

我想了兩種方法：

1. 字符串拼接
2. 依次打印

兩種思路代碼如下：

//依次打印
sum=0
for ((i=1; i<=100; i++))
do
    if [ $i -eq 100 ];then
        echo -n "$i="
        break
    fi    

    echo -n "$i+"
    let sum+=i
done
echo $sum

//字符串拼接
sum=0
i=1
str=""
while test $i -le 100
do
    if [ $i -eq 100 ];then
        str=$str$i"="
        break
    fi

    str=$str$i"+"
    let sum+=i
    let i++
done
echo $str$sum

---

---

利用函數實現三個數的最大值，三個數需要從命令行傳入

function max_min()
{
    max=$1
    min=$1

    for i in $@
    do
        if test $max -lt $i ;then
            max=$i
        fi
        if [ $min -gt $i ]; then
            min=$i
        fi
    done

    echo "max = $max"
    echo "min = $min"

}

max_min $1 $2 $3

---

---

顯示進度條

str=''
arr=( "|" "/" "-" "\\")
count=0

for ((i=0; i<=100; i++))
do
    printf "[%-100s][%d%%][%c]\r" "$str" "$i" "${arr[count]}"
    str=$str'#'
    let count++
    let count%=4
    sleep 0.05
done

#echo ""
printf "\n"

彩色進度條

function f()
{

    local color='\033[45m'
    local clear='\033[0m' 
    str=''
    arr=( "|" "/" "-" "\\")
    count=0

    for ((i=0; i<=100; i++))
    do
        printf "$color[%s][%d%%][%c]$clear\r" "$str" "$i" "${arr[count]}"
        str=$str' '
        let count++
        let count%=4
        sleep 0.05
    done

    #echo ""
    printf "\n"
}

f  #調用函數

---

---

斐波那契

說明：爲了儘快熟悉shell語法，Fib採用三種方法實現

function Fib()
{
    local first=1
    local second=1
    local third=$(( $first+$second ))
    if [ $1 -le 0 ];then
        echo "$1 should be > 0"
        exit -1
    elif [ $1 -eq 1 -o $1 -eq 2 ];then
        echo 1
        exit 0
    fi


    i=3
    while [ $i -le $1 ]
    do
        let third=first+second
        let first=second
        let second=third
        let i++
    done

    echo $third
}

function FibArr()
{
    local arr=()
    arr[1]=1
    arr[2]=1

    if [ $1 -le 0 ];then
        echo "$1 should be > 0"
        exit -1
    elif [ $1 -eq 1 -o $1 -eq 2 ];then
        echo 1
        exit 0
    fi

    i=3
    while test $i -le $1
    do
        let arr[i]=arr[i-1]+arr[i-2]
        let i++
    done
    echo ${arr[$1]}
}

function FibR()
{
    if [ $1 -eq 1 -o  $1 -eq 2 ];then
        echo 1
        exit 0
    fi

    pprev=$(( $1-2 ))
    prev=$(( $1-1 ))

    pprev_ret=$(FibR $pprev)
    prev_ret=$(FibR $prev)
    ret=$(( pprev_ret+prev_ret ))
    echo $ret
}

FibR $1

Fib $1

FibArr $1

---

---

求平均值，精度保證兩位小數

if [ $# -lt 3 ];then
    echo "please input at least 3 arg"
    exit -1
fi

max=$1
min=$1
sum=0
for i in $@
do
    #if [ $max -lt $i ];then
    #    max=$i
    #fi

    #if [ $min -gt $i ];then
    #    min=$i
    #fi
    [ $max -lt $i ] && max=$i
    [ $min -gt $i ] && min=$i 
    let sum+=i
done

echo "max=$max"
echo "min=$min"
echo "sum=$sum"
avg=` echo "scale=2; $sum / $#" | bc`
echo "avg=$avg"

改變字符串

123abc456
123def456

改爲

123ABC456
123DEF456

while read line
do
    part1=` echo $line | cut -c 1-3 `
    part2=` echo $line | cut -c 4-6 | tr '[a-z]' '[A-Z]' `
    part3=` echo $line | cut -c 7-9 `
    echo $part3$part2$part1
done < file > newfile