[Bug-ddrescue] os x external drive w/ bad blocks

[Ryan Clark]

Hi,

I'm new to macs, less than a year, so I apologize for any ignorance  
here.

I understand that GNU ddrescue is not specifically for os x (10.4)  
but that it could possibly be used on it.

Here is my problem:

I dropped an external... which will not mount.  I ran diskwarrior for  
32 hours and accidentally unplugged it although there were no signs  
of it getting anywhere.  Data Rescue hangs up entirely only 170mb  
in.  Once, it did recognize bits of my original underlying file  
structure which is giving me the hope that some of the data is still  
there among the bad blocks.  Disk utility says b-tree node invalid.   
Surface scan gives me an arch of read times, off the charts on the  
sides and normal in the middle.

I cam across your program looking for something that can make a clone  
of the drive while skipping the bad blocks, instead of hanging for  
hours on them, possibly refilling it with zeros or something.  The  
blocks keep getting worse and I am certain that it is hardware  
failure in the drive. Everything hangs right away except I can run a  
read/write scan across the whole disk.  I hope to run data rescue on  
the clone with zeroed out bad blocks afterwards and see if anything  
at all is left of my swiss-cheesed data.

Have I come to the right program?  Does my plan make sense?

How I need help:

I apologize, but could you give me step by step instructions, b/c I  
have barely used terminal at all yet, being new to macs and I dont  
know the language.  I hope to copy from old external to new external.

how do i install the program via terminal first off.

THANK YOU FOR YOUR HELP>

I apologize for my ignorance.