shell while的用法

1.

#!/bin/sh
int=1
while (( "$int < 10" ))
do
echo "$int"
let "int++"
done

2.
#!/bin/sh

sum=0
int=1

while (( "$int < 100" ))
do
let "sum+=int"
let "int+=2"

done
echo "the sum is $sum"

3.
#!/bin/sh
echo "please input the num(1-10)"
read num
while [[ "$num"!=4 ]]
do
if [ "$num" -lt 4 ]
then
echo "the num is too large,please input again"
read num
elif [ "$num" -gt 4 ]
then
echo "the num is too small,please input again"
read num
else
echo "right you are right"
exit 0
fi
done

echo "right you are right"

4.
#!/bin/sh
echo "please input the num"
read num
sum=1
while [ "$num" -gt 0 ]
do
let "sum=sum*num"
let "num--"

done

echo "the sum is $sum"

5.
#!/bin/sh
echo "please input the num(1-10)"
read num
signal=0

while [[ "$signal" != 1 ]]

do
if [ "$num" -lt 5 ]
then
echo "the num is too small,please try again"
read num
elif [ "$num" -gt 5 ]
then
echo "the num is too large please try again"
read num
else
echo "you are right"
let "signal=1"
fi

done

6.
#!/bin/sh
echo "the par num is $#"
echo "what you input is"

while [[ "$*" != "" ]]
do
echo "$1"
shift
done