there are two issues related to how ROOT is processing the command line input:
- is it intentional that ROOT  doesn't display more than 80 characters 
in the command line? -  regardless the X-window size instead of
root [5] TFile* f = new TFile("/data34/upgrade/ift/murat/isl/mbr_proc_001.3.cl./upgrade/ift/murat/isl/mbr_proc_001.3.cl.root")
ROOT displays either 
root [5] TFile* f = new TFile("/data34/upgrade/ift/murat/isl/mbr_proc_001.3.cl$
or
$4/upgrade/ift/murat/isl/mbr_proc_001.3.cl.root")
- the second remark is very technical:
  when deleting or inserting a character in the middle of ROOT command one 
  observes *very* large (in the relevant time scale) delays between the moment 
  when key is pressed and the corresponding change occurs on the screen. It 
  points out to a pretty inefficient implementation of the command line editing.
  What about using GNU readline library, for example?
					Thanks, Pasha