I’ve been having some issues with a physical standby running Oracle 10.2.0.3. This has caused us to have to manually register logfiles to bridge gaps in the archive sequence on the physical standby.
One way of registering a logfile is via the following:
SQL> alter database register logfile
'/var/arch/arch_1_101.arc';
So this is a straightforward way of registering a logfile giving the full path to the logfile. However, what if you have a very large number of logfiles to register, the above does not really scale all that well. Thankfully there is an rman command that enables you to register all logfiles within a directory:
rman> catalog start with '/var/arch';
This can save you a lot of time if you need to register a large number of files.
jarneil 
Wow! Thanks for this tip. I was asked to verify that a standby database was current and discovered that the dba responsible had not been monitoring it for almost a year, and there were a lot of gaps in the archive logs. This was a total time saver as opposed to restoring the missing logs to production and letting the standby request them!
Thanks !!! You just saved me about 5hrs of manually registering logfiles
Thanks !! You have saved few hours for me ..
Very good and very userful tip
FOR ME IT SAVED MY 10 TO 15 HOURS TO REGISTER LOGFILES. THANKS