use strict; my $fpath = 'blah.dat'; open(FILEHANDLE_1, ">", $fpath); print "Opened file '$fpath' into FILEHANDLE_1.\n"; flock(FILEHANDLE_1, 2); print "Put exclusive lock on FILEHANDLE_1\n"; close(FILE_HANDLE_1); print "Closed FILEHANDLE_1. It should now be possible to put an exclusive lock on file '$fpath'\n"; open(FILEHANDLE_2, ">", $fpath); print "Opened file '$fpath' into FILEHANDLE_2.\n". "Will now try to put an exclusive lock on it.\n"; flock(FILEHANDLE_2, 2); print "Successfully put exclusive lock on FILEHANDLE_2\n";