#!/bin/bash

myTest="hello world"

myNum=30

yourNum=40

val=`expr $myNum + $yourNum`

echo $val

val=`expr $myNum \* $yourNum`

echo "$val"

val=`expr $myNum / $yourNum`

echo "$val"

echo ${myTest:1:4}

array=(1 2 3 4 5)

array2=(aa bb cc dd ee)

value=${array[3]}

echo $value

value2=${array2[3]}

echo $value2

length=${#array[*]}

echo $length

echo "hello world"

echo helo world

text="hello world"

echo $text

echo -e "hello \nworld"

echo "hello world" > a.txt

echo `date`

test $[myNum] -eq $[yourNum]

test myNum=yourNum

for i in {1..5}

do

    echo $i + "  djq"

done

for FILE in /etc/p*

do

    echo $FILE

done

COUNTER=0

while [ $COUNTER -lt 5 ]

do

        COUNTER=`expr $COUNTER + 1`

        echo $COUNTER

done

echo 'input...'

while read FILM

do

        if [ $FILM == "exit" ]

        then

                break

        else

        echo "great $FILM"

        fi

done

sysout(){

        echo "hello world sysout"

}

sysout

calc(){

        anum=$1

        echo $anum

        bnum=$2

        echo $bnum

        echo $#

        echo $*

        return $(($anum + $bnum))

}

calc 44 55

result1=$?

echo $result1

$echo result1 > a.txt

echo input < /etc/passwd