How to find the file in between some days & delete the same?

Follow the below steps to find out the particular modified file in between 20 to 30 days & delete the same.

Command to find and list the file

#find / -mtime +20 -mtime -30 -type f -name test.* -exec ls -al {} \;   

Command to delete the listed file.

#find / -mtime +20 -mtime -30 -type f -name test.* -exec rm {} \;

As per your needs, change the file name.

Hope it helps.