There most likely is. What is the format of your files?

The function for you to read about is Import:

http://reference.wolfram.com/language/ref/Import.html

Nilanjan,

You can use * wildcard to import all files:

SetDirectory[NotebookDirectory[]] ;
(* export test files *)
Export["eg01.dat",1] ;
Export["eg02.dat",2] ;
Export["eg03.dat",3] ;
Export["eg10.dat",10] ;
(* import all test files *)
Import["eg*.dat"]?

I.M.

HI Nilanjan,

What is difficult about your question is that your are describing your files in general terms but not actually explaining their exact format. What you are asking for is completely doable but the details depend on the exact format of your data. Without that there isn't a way for someone to tell you what specific code to write to complete your task. Do you have a different file for each time? And, if so, then does each such file have two columns: redshift and position? And also, if so, is the time specified in the file's name or is it somehow in the file itself?

In any case it will help to give you some answers if you either (a) give a detailed specification of the files and the filenames and/or (b) give a set of example files.

I'm sure we'd all like to help, but we need your help with the actual details ;-)

Best, David