need command to delete previous days backup instead of obselete

i have shell script which takes back up and delete based on obselete.

source .t45pdbprofile


echo

rman target / <
backup database plus archivelog all delete input;

delete no prompt obselete;

eof
exit


Can any one help me with a command deleting old backups based on time like sysdate -1 or sysdate -2 instead of saying delete obselete.the backups are on ASM

Thank you