Any time you have multiple processes contending for the same resource, you should implement file locking. open (FILE,">>logfile) or die'; #open the file flock(FILE,2); # lock it up seek(FILE,0,2); # in case someone wrote after the open #print, etc here print FILE "Log data\n"; # old versions of perl might need an explicit flush here flock (FILE,8); #unlock it close(FILE); #close it down