shellscript conditional to check for external disk

[Chuck Robey]

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Helge Rohde wrote:
> Hello List,
> 
> I need to write a backup script, and one of the required actions would be a 
> copy of the backup to an external firewire drive. I would like to make this 
> as easy as possible for the local staff, so i'd like to check whether the 
> drive is attached, if necessary mount it, copy over the backup  and unmount 
> it again, so that the local staff can swap the external disks when they're 
> not used.
>  
> Is there a canonical way to achieve what i want? I played with the idea of 
> simply checking for /dev/da0s1d's existance, but that won't disappear on 
> disconnect, so that would leave the  is a possibility that although da0 is 
> in /dev, it might not be connected.
> 
> Any ideas or RTFM-pointers?

I'm not certain this will do what you want with enough security, but if you put
the commands in to mount the dist into /etc/fstab, then later on your ask simply
"mount <diskname>", mount will follow those rules to mount the disk, if it's
indeed in existence.  Putting that into a script is pretty simple.  There are a
huge number of backup commands ... I rather like tar, which can be made to
automatically compress the output, or to ask for a single file out of the whole
archive, on restoral.  Either way, not hard to automate.

Does this fit what you wanted?  There's a good man page on fstab, and y9ou
shouold read the pages on mount and tar.

> 
> Helge
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