Hi Rahul,
The brtools will work for Linux as well so you need to follow up the same options as mentioned in the thread provided by Gaurav.
Select space management-->Extend Tablespace and the remaining options as mentioned.
Also you can try to use the oracle sql commands like below if required.
alter tablespace <name> add datafile '<location/name>' size 8G autoextend off;
Let us know if this worked for you.
Regards,
Ram
