shell打印菱形和设置文字颜色背景色

shell脚本在linux日常维护当中经常会用到，例如部署项目或者运维等，本文介绍两个脚本，分别是打印菱形和修改输出脚本背景色和颜色，本文参照这篇全英文文章稍作修改

一、打印菱形

直接上代码

#!/bin/sh
MAX_NO=0
echo -n "Enter Number between (5 to 9) : "
read MAX_NO
if ! [ $MAX_NO -ge 5 -a $MAX_NO -le 9 ] ; then
        echo "WTF... I ask to enter number between 5 and 9, Try Again"
        exit 1
fi
clear
for (( i=1; i<=MAX_NO;i++ )) 
do
    for (( s=MAX_NO;s>=i;s-- ))
        do
            echo -n " "
        done

    for (( j=1; j<=i; j++ ))
    do
        echo -n " ."
    done
    echo ""
done
for (( i=MAX_NO;i>=1;i-- ))    
do
    for (( s=i; s<=MAX_NO; s++ ))
    do
        echo -n " "
    done

    for (( j=1; j<=i; j++ ))
    do
        echo -n " ."
    done
    echo ""
done