hi,
if i delete a file from /home/san/abc.cpp in linux/unix
and i want to restore it back
how to do that ?
There is no 'undelete' command. You have to restore from tape. OR some other backup.
where do you have the backup? tape... etc. if there isn't a backup you can't restore the files...
edit: jim was faster 
Depends entirely on what sort of backup arrangement you have. Undeleting a file from an ext3 partition is not usually realistically doable.