$ ls [a-d,A-D]*.jpg
This would list all the files that have an extension as .jpg and have as their first letter either a,b,c,d,A,B,C or D . The [ , ] imply that this entire range indicates ONLY ONE letter which can be from any of the two given sub-ranges. A comma is used to merge different range of letters or numbers.
Note : I would once again like to mention that [a-d,p-z] does NOT mean that there can be two letters, the first one from a to d and the second one from p to z. It means that there is ONLY ONE letter, and that letter can be from either a to d or from p to z.
ресурс откуда взят текст
http://www.codecoffee.com/tipsforlinux/articles/26-1.html