Copy or move large file with transient name till the file is completely transfered to destination in linux

Question

I am trying to copy/move a large file (15 GB) to a directory in Linux and want to have a dependency on that event. Now lets say I have a file named abc.txt, and I am running below command:

mv /usr/tmp/abc.txt /usr/data/

When the move process start I see a file in data directory with the actual file name i.e. abc.txt but with data still being in transit. As the data directory list the file abc.txt in its directory my dependent process thinks that the file is available and it start the dependent process however the file is not completely moved and hence my dependent process triggers prematurely.

Is there a way I can move a file with transient name i.e. while the data transfer is going on it will use a transient name(some swap file name) and change the name to actual file when it is completely transferred?

Answer 1

You must be moving between two different filesystems, so in effect the file is copied. Try to first copy it then, and after that's done, move within the destination. This should do:

mv /usr/tmp/abc.txt /usr/data/.abc.txt && mv /usr/data/.abc.txt /usr/data/abc.txt

I assume your watching process won't recognise the hidden file. Otherwise you could make a temp directory at the target location or something similar.