I need to sort a list of files based on aphabetical order, and files in each such group should be in sorted in timestamp.

ie,

Resultant Files list should look like ,
Files-names starts with A in sorted timestamp, then
Files-names starts with B in sorted timestamp then
Files-names starts with C in sorted timestamp and so on.

Please help.

man sort

it lets you sort based on columns.

Example : If I list files in a directory ( ls -lrt ) it shows like below.

c3
b4
b3
a4
a3
c2
b2
c1
b1
a2
a1

What I need is

c3
c2
c1
b4
b3
b2
b1
a4
a3
a2
a1

How can this be achieved using a command. ?

porter has advised to look at the man pages. Quote :
so based on requirement, "sort -r filename" will do it. Read the man pages like : "man command-that-you-are-interested-in"