[Tutor] Reading directory

[arkamir at softhome.net]

My question is sorta difficult to explain so bear with me. I need to read a 
directory and select distinct files which are distinct before a certain 
point. Similiar to SQL select distinct. So if i had a directory filled with: 

family_01.jpg
family_02.jpg
family_03.jpg
family_03.jpg 

test_01.jpg
test_02.jpg 

It would optimilly select just.
family
test 

Or the whole file name and then filter everything past the _.
I hope I explained this clearly enough. I need this because I'm making an 
online photo album for my family and want to minimize recoding html by 
having the links to each section dynamincally generated. I am using Linux. 

Thanks a lot!!!