Hi Altaf,
there should be an entry related to your command in alert.log. Like this:
Alert.log
Thu Nov 13 15:35:10 2014
alter database backup controlfile to trace
Backup controlfile written to trace file /oracle/<SID>/saptrace/diag/rdbms/<sid>/<SID>/trace/<SID>_ora_9058.trc
Completed: alter database backup controlfile to trace
Does your command finish with "Database altered" ?
Best,
Serhat