suggest a query about recover after rm

[Ramírez Sánchez-Escobar José Julio]

I'm working under:
Linux 2.4.21-sgi300r3 #1 SMP Wed Apr 21 18:30:04 PDT 2004 ia64 ia64 ia64 
GNU/Linux
I would like to make a query about rm'ing files.
If i check the man about the rm command, I can see there:
       Note  that  if  you  use rm to remove a file, it is usually possible to
       recover the contents of that file.  If you want more assurance that the
       contents are truly unrecoverable, consider using shred.
Sometimes I have needed recovering files after rm'ing (not moved to a trash 
folder) 
but I do not know how.
Is there any command/tool implemented in linux/unix for this purpose?.
This is not a bug.
Thank you,
JJ