shell if学习

 1 #!/bin/sh
#echo "Hello# World !"
#your_name='qinjx'
#str="Hello, I know your are \"$your_name\"!\n "
#echo "英文${str}ohyes"

# 终端输入处理
read -p "请输入您的分数（0-100）：" grade

# 合法性校验
if [ -z "$grade" ]; then
    echo "您没有输入分数"
    exit

#fi  #这个是自己在网上找到添加的，因为输入字母就出错了

#if echo $grade | grep -q '[^0-9]'
#then
#        echo "this is not a num,please input num"
#        exit
fi

if [ $grade -gt "100" -o $grade -lt "0" ]; then
    echo "您输入的分数不在0-100范围内"
    exit
fi
# 计算等级
if [ $grade -ge "90" -a $grade -le "100" ]; then
    echo "好极了，您的评分为： A"
elif [ $grade -ge "80" -a $grade -le "89" ]; then
    echo "很好。您的评分为 B"
elif [ $grade -ge "70" -a $grade -le "79" ]; then
    echo "好。您的评分为 C"
elif [ $grade -ge "60" -a $grade -le "69" ]; then
    echo "不错。您的评分为 D"
elif [ $grade -lt "60" ]; then
    echo "回去挨打吧"
fi

shell if....then,很好的一个学习代码，一眼就明白了

 

for循环

#!/bin/bash
#数字性循环
#第一种 
for((i=1;i<=10;i++));
do 
echo $(expr $i \* 3 + 1);
done
#
#
#
##第二种 
for i in $(seq 1 10)
do 
echo $(expr $i \* 3 + 1);
done
#
#
##第三种
for i in {1..10}
do
echo $(expr $i \* 3 + 1);
done
#
#
##第四种
awk 'BEGIN{for(i=1; i<=10; i++) print i}'
#
#
##字符性循环
##第一种
for i in `ls`;
do 
echo $i is file name\! ;
done
#
##第二种
for i in $* ;
do
echo $i is input chart\! ;
done
#
#
##第三种
for i in f1 f2 f3 ;
do
echo $i is appoint ;
done
#
##第四种
list="rootfs usr data data2"
for i in $list;
do
echo $i is appoint ;
done
#
#
##路径查找
##第一种
for file in /home/cyl/下载/*;
do
echo $file is file path \! ;
done
#
##第二种
for i in $(ls *.sh)
do
echo $file is file path \! ;
done