There is hidden and undocumented Oracle utility available called DBFSIZE. This Oracle utility provides exact size of file, which is connected with Oracle software.
Means we can get size of control file, redo log file, datafile size using DBFSIZE undocumented Oracle utility.
DBFSIZE utility doesn’t available for Windows platforms.
How to use DBFSIZE utility of Oracle?
DBFSIZE provides number of blocks and size of block in output of Database file size (check below example first number stands for number of blocks and second number stands for size of each block)
$ dbfsize indx.dbf
Database file: indx.dbf
Database file type: file system
Database file size: 4196 8192 bytes blocks
$ dbfsize control.ctl
Database file: control.ctl
Database file type: file system
Database file size: 162 14324 bytes blocks
$ dbfsize redo1a.log
Database file: redo1a.log
Database file type: file system
Database file size: 20480 512 bytes blocks
DBFSIZE is helpful to counter checking backup file size and current file size of Oracle database.