学习Linux第七天

1.shell

echo $HOME

默认在shell中编写的变量全部是局部变量，如果重新打开console的话，那么这些变量将全部丢失，全局的变量可以写在文件~/.bashrc文件。

2.判断

!/bin/sh
#if-elif-else-fi
user_input_fruit = "";
echo -e "please input a kind of fruit:\r";
read user_input_fruit;
if [ $user_input_fruit = "apple" ]
then
    echo -e "You input \e[1;32mAPPLE\e[0m!\r";
elif [ $user_input_fruit = "grape" ]
then
    echo -e "You input \e[1;34mGRAPE\e[0m!\r";
else
    echo -e "Please input a kind of \e[1;36mFRUIT\e[0m!\r";
fi

3.循环

!/bin/sh
#for-do-done
user_input_number=1;
echo "please input a number:";
read user_input_number;
i=0;
for (( $i=0; $i<$user_input_number; $i++))
do
    echo $i,"\r";
done

!/bin/sh
#while loop
n=10;
i=0;
while [ $i -le $n ]
do
    echo $i." ";
done

!/bin/sh
#case-in-;;-esac
user_input_genda="male";
echo "tell me your genda:\r";
read user_input_gendar;
case $user_input_gender in
    "male")
        echo "Wo, good man\r";;
    "female")
        echo "Ohh,smart girl\r";;
    *)
        echo "You must be jokking\r";;
esac