Instructions
Open your server's file manager. Depending on where you host your server, this process will vary, but most cPanel options feature a "File Manager" link.
Write down the names of the tablespaces you wish to modify.
Load Oracle Database on your server. Again, depending on where you host your server, this process will vary greatly.
Type in the following SQL command, replacing "x" with the name of the tablespace you wish to modify, to get tablespace usage:
ALTER TABLESPACE x READ WRITE;