There is a daemon which is constantly writing to this particular nohup.out file.This daemon can't be stopped. But the large size of this file is hampering the directory space.I want to write a script which will wait for 48 hours and then delete the contents of the file ( nohup.out ), but not the file.
"all 48 hours" -> set up a cron job doing that every 2nd day.
Try to just do something like
> yourlog
If the demon doesn't keep a file handle open on this log, it will be zeroed. Else you might want to check if there is any log options for this demon or maybe stop it, zero the log and start it again.