Bash append file to date and time format

Some people would like to export or append your file or log name after the date and time format, like this YYMMDD_MMHHSS.

i have a script it is able to append in this style

@ECHO OFF
set datetime=%date:~0,4%-%date:~8,2%-%date:~0,2%_%time:~0,2%%time:~3,2%%time:~6,2%
set datetime=%datetime: =0%
echo hello >>%datetime%.txt
EXIT

It will output like this "2020-17-20_104919.txt"

if you don't want the second just modify like this

set datetime=%date:~0,4%-%date:~8,2%-%date:~0,2%_%time:~0,2%%time:~3,2%%time:~4,0%

Resource: 

https://stackoverflow.com/questions/1192476/format-date-and-time-in-a-windows-batch-script