1.echo.sh
#!/bin/bash
#test
echo "======================================"
echo -n "input number:"
read a
echo "number=$a"
#this number also can be input
function ran(){
min=$1
max=$(($2-$min+1))
num=$(cat /dev/urandom | head-n 10 | cksum | awk -F ' ' '{print $1}')
echo $(($num%$max+$min))
}
for ((i=1;i<=a;i+=2))
do
for((k=0;k<(i-1)/2;k++ ))
do
echo -n " "
done
for((j=i;j<=a;j++))
do
nu1=$(ran 30 37)
nu2=$(ran 40 47)
m=`echo -e"\033[$nu2;$nu1;5m*\033[0m "`
echo -n $m
done
echo ' '
done
chmod +x echo.sh
./echo.sh
2.
date -d "10 days ago"
date -d "-20 days ago"
