[gentoo-user] Process to resize ext3 file system at the command line?

Hi,
I've got a 3-disk 250GB RAID-1 that I use for short term, on the
machine backups. It's normally not mounted unless I'm doing a quick
save. Unfortunately it's a bit too small these days so I'm therefore
going to convert it to a 3-disk RAID-5 which will double it's size.

I'm pretty sure I've got the command set right to do the RAID-1 to
RAID-5 conversion, but once it's done I believe the file system itself
will still be 250GB so I'll need to resize the file system. In the
past I've done this with gparted, which seems to work fine, but this
time I was considering doing it at the command line. Does anyone know
of a good web site that goes through how to do that? I've browsed
around and found different pages that talk about it but my reading
looks like they all have minor differences which leaves me a bit
worried.

Note that the status of the backup is currently good but if I
happen to lose the data on that partition it won't likely be a big
problem. I'm just trying to get to the end of the process without
losing it if possible.

Thanks,
Mark