shell脚本中使用if和bc比较变量值和指定值

##【预备知识】
假如我有个日志文件，每天会往里追加。日志摘要如下——
2018-06-12 09:08:56,105 - hdfs.client - INFO - Renaming ‘/apps/wps_prt_feature/business_info/2018-06-11/android_app.temp-1528765731’ to ‘/apps/wps_prt_feature/business_info/2018-06-11/android_app’.
… …
2018-06-12 09:09:29,392 - hdfs.client - INFO - Renaming ‘/apps/wps_prt_feature/business_info/2018-06-11/ios_app.temp-1528765764’ to ‘/apps/wps_prt_feature/business_info/2018-06-11/ios_app’.

我想在里面找到带有当天日期和Renaming字样的内容，以便确认我跑的作业成功了，
那么我就想用shell脚本从日志文件中过滤出来。如何实现呢？下面是思考的过程——

[tony@test-host-10 business_info]$ today=`date +%F`	# 获取当天日期
[tony@test-host-10 business_info]$ echo $today 
2018-05-24

从包含当天日期的日志记录中进一步筛选出含有Renaming的日志

[tony@test-host-10 business_info]$ grep $today log_fifth | grep Renaming | wc -l
2
[tony@test-host-10 business_info]$