Re^3: read file line by line then do something and write to same file

in reply to Re^2: read file line by line then do something and write to same file
in thread read file line by line then do something and write to same file

A cursory strace perl -pi reveals a more sloppy pattern than described, however. I see open/unlink/open/read+write/close/close. The unlinked source file is still readable; it gets released upon close.

A relatively safe update sequence is: mkstemp/read+write/fsync/rename. The final rename is atomic, but that itself does not prevent races with multiple updaters (of course).

Comment on Re^3: read file line by line then do something and write to same file

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Re^4: read file line by line then do something and write to same file by davido (Cardinal) on Jun 16, 2014 at 19:44 UTC
Yes, I believe you're correct regarding the `strace`. I recall now that the documentation is not 100% truthful as to what is happening behind the scenes. If you use `-i.bak` instead of `-i`, you'll probably see an open/rename/open/read+write/close/close instead of open/unlink... Dave	[reply] [d/l] [select]

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