That's wrong. It suffers from a race condition.
+===============================+===============================+
| Process 1 | Process 2 |
+===============================+===============================+
| open the status file | | T
| read the status (status is 1) | | i
+-------------------------------+-------------------------------+ m
| | open the status file | e
| | read the status (status is 1) | |
| | write 2 to the status file | |
| | proceed | |
+-------------------------------+-------------------------------+ v
| write 2 to the status file | |
| proceed | |
+===============================+===============================+
If you use flock, then it's just an extention of what the OP posted.
( Oops! Seems like tye posted something similar when I was writing this node. )
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