time1=$(date)
echo $time1

time2=$(date "+%Y%m%d%H%M%S")
echo $time2

time3=$(date "+%Y-%m-%d %H:%M:%S")
echo $time3

time4=$(date "+%Y.%m.%d")
echo $time4

# 1. 取今天时间
now=`date -d "now" +%Y-%m-%d`
echo $now

# 2.取昨天时间
yesterday=`date -d "yesterday" +%Y-%m-%d`
echo $yesterday

# 3.获取前n天

daysago=`date -d "2 days ago" +%Y-%m-%d`

echo $daysago

[root@Server-rm8glb ~]# sh time.sh
2020年 04月 14日 星期二 23:21:34 CST
20200414232134
2020-04-14 23:21:34
2020.04.14
2020-04-14
2020-04-13
2020-04-12