#!/bin/bash
echo "helloworld!"

#hello="helloworld!"

#echo $hello

#name='qincasin'

#hello='Hello,I am '$name'!'

#echo $hello

name="qincasin"
# 使用雙引號(hào)拼接
greeting="hello , "$name"!"
greeting_1="hello,${name}!"
echo $greeting $greeting_1
# 使用單引號(hào)拼接
greeting_2='hello,'$name'!'
greeting_3='hello,${name}!'
echo $greeting_2 $greeting_3

# 截取字符串長(zhǎng)度
str="qincasin"
# 第一種方式
echo ${#str}
#第二種方式
expr length $name

# expr 表達(dá)式的運(yùn)算符必須要左右都有空格，否則直接輸出表達(dá)式
expr 5+6 
expr 5 + 6

# expr 5 * 6 表達(dá)式錯(cuò)誤 ，需要轉(zhuǎn)義字符進(jìn)行轉(zhuǎn)換
expr 5 \* 6

# 簡(jiǎn)單字符串截取
# 從字符串第1個(gè)字符開始往后截取3個(gè)字符
str2="qincasin"
echo ${str:0:3} # qin

# 根據(jù)表達(dá)式截取
var="http://www.runoob.com/linux/linux-shell-variable.html"
s1=${var%%t*} #h
echo $s1
s2=${var%t*} #http://www.runoob.com/linux/linux-shell-variable.h 
echo $s2
s3=${var%%.*} #http://www
echo $s3
s4=${var#*//} #/www.runoob.com/linux/linux-shell-variable.html
echo $s4
s5=${var##*/} #linux-shell-variable.html
echo $s5


# shell 數(shù)組
array=(1 2 3 4 5)
# 獲取數(shù)組長(zhǎng)度
length=${#array[@]} # 5
length2=${#array[*]}
echo ${length} ${length2}

# 輸出數(shù)組第三個(gè)元素
echo ${array[2]}
echo ${array[*]}
#刪除下表為1的元素
unset array[1] 
echo ${array[*]}

# 遍歷輸出
echo '遍歷輸出數(shù)組'
for i in ${array[@]};
        do echo $i;
        done

# 刪除數(shù)組中所有元素 數(shù)組為空
unset array;
#echo ${#array[*]}
for i in ${array[@]};
do echo $i;
done

# shell 基本運(yùn)算符
# 算數(shù)運(yùn)算符
echo "算數(shù)運(yùn)算符號(hào)"
a=10
b=20
expr $a + $b
expr $a - $b
expr $a \* $b
expr $b / $a
expr $b % $a 
a=$b
echo $a
a=10

#關(guān)系運(yùn)算符號(hào)，不支持字符串，只限數(shù)字，除非字符串是數(shù)字
echo '關(guān)系運(yùn)算符號(hào)'
#輸出B
score=90;
maxscore=100;
if [ $score -eq $maxscore ]
then
    echo 'A'
else
    echo 'B'
fi
# 邏輯運(yùn)算符
echo '邏輯運(yùn)算符'
# 邏輯與運(yùn)算只有相與的兩邊都是1，與的結(jié)果才是1，否則與的結(jié)果是0
c=$((1&&0))
echo $c;
#布爾運(yùn)算符號(hào)
echo '布爾運(yùn)算符號(hào)'
echo '! 非運(yùn)算'
echo '-o 或運(yùn)算，有一個(gè)表達(dá)式為true,則返回true'
echo '-a 與運(yùn)算，兩邊表達(dá)式都為true才返回true'
#字符串運(yùn)算符
echo '字符串運(yùn)算符號(hào)'
echo $a $b
d="abc"
e="efg"
if [ $d = $e ]
then
    echo "a等于b"
else
    echo "a不等于b"
fi
#文件相關(guān)運(yùn)算符
# -r 可讀
# -w 可寫
# -x 可執(zhí)行
# -s 是否為空
file="/home/code/shell/test.sh"
if [ -x $file ]
then
    echo "可執(zhí)行文件"
else
    echo "不可執(zhí)行"
fi
echo "------------------------" 
# shell 流程控制
echo "shll流程控制"
echo "if 條件語(yǔ)句 "
echo $a $b
if [ $a = $b ]
then
    echo "a等于b"
elif [ $a > $b ]
then
    echo "a大于b"
else
    echo "a小于b"
fi
 echo "------------------------"
echo "for 循環(huán)語(yǔ)句"
echo "輸出當(dāng)前列表中的數(shù)據(jù)"
for loop in 1 2 3 4 5
do
    echo "當(dāng)前的數(shù)據(jù)為:$loop"
done
echo "------------------------"
echo "產(chǎn)生10個(gè)隨機(jī)數(shù)"
for i in {0..9}
do
    echo $RANDOM;
done
echo "------------------------"
echo "輸出1到5"
for((i=1;i<=5;i++));do
    echo $i;
done
echo "------------------------"
echo "while語(yǔ)句"
int=1
while(($int<=5))
do
    echo $int
    let "int++"  # 或者let int++
done
echo "------------------------"
#echo "while循環(huán)用于讀取鍵盤信息"
#echo "按下 <CTRL-D> 退出 "
#echo -n "請(qǐng)輸入你最喜歡的電影:"
#while read FILM
#do
#   echo "是的！$FILM 是一個(gè)好電影"
#done

echo "------------------------"
## shell 函數(shù)
echo "shell 函數(shù)"
#echo "------------------------"
echo "不帶參數(shù)沒(méi)有返回值的函數(shù)"
func(){
    echo "這是第一個(gè)shell函數(shù)!"
}
func
echo "------------------------"
echo "有返回值的函數(shù)"
funcWithReturn(){
    echo "第一個(gè)數(shù)字:"
    read aNum
    echo "第二個(gè)數(shù)字:"
    read anotherNum
    echo "兩個(gè)數(shù)字分別是$aNum 和 $anotherNum !"
    return $(($aNum+$anotherNum))
}
funcWithReturn

echo "輸入的兩個(gè)數(shù)的和為: $?"
echo "------------------------"
echo "帶參數(shù)的函數(shù)"
funWithParam(){
    echo "第一個(gè)參數(shù) $1 !"
    echo "第二個(gè)參數(shù) $2 !"
    echo "第三個(gè)參數(shù) $3 !"
    echo "第四個(gè)參數(shù) $4 !"
    echo "第五個(gè)參數(shù) $5 !"
    echo "第六個(gè)參數(shù) $6 !"
    echo "第七個(gè)參數(shù) $7 !"
    echo "第八個(gè)參數(shù) $8 !"
    echo "第九個(gè)參數(shù) ${9} !"
    echo "第十個(gè)參數(shù) $10 !"
    echo "第十一個(gè)參數(shù) $11 !"
    echo "參數(shù)總數(shù)有 $# 個(gè)!"
    echo "作為一個(gè)字符串輸出所有參數(shù) $*"
}
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