tar -cf not preserving exact modification time

tar

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When creating a tar archive with -c, the modification time seems to be changing, specifically it cuts off the time after the decimal, leaving the modtime to be just the integer value of what it was.

Notice: ```

[localhost] $ mkdir test
[localhost] $ stat test
  File: ‘test’
  Size: 4096        Blocks: 8          IO Block: 4096   directory
Modify: 2016-07-18 17:01:33.116807520 -0400 # <------ Notice exact time
[localhost] $ tar -cf test.tar test
[localhost] $ tar -xf test.tar
[localhost] $ stat test
  File: ‘test’
  Size: 4096        Blocks: 8          IO Block: 4096   directory
Modify: 2016-07-18 17:01:33.000000000 -0400 # <------ Notice how time is rounded

(I removed irrelevant parts from output of stat for readability)

I've inquired man tar, but couldn't find an option that'll preserve exact modification time in nanoseconds. Could someone explain why such behavior is occurring? Or is this expected during tar creation.

Update: So far no luck, I tried playing around with tar options but most of options that deal with time are related to a files' access time, and not modtime. The ones that do deal with modtime change the modtime, which isn't something I'm looking for.

Автор: steve Источник Размещён: 18.07.2016 03:07

Ответы (1)


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Just in case anyone googling the same issue stumbles upon this thread (like I did):

The solution (at least one of them) is to use the -H option, as answered here:

https://unix.stackexchange.com/questions/397130/tar-how-to-preserve-timestamps-down-to-more-than-a-second-of-precision/397132#397132

The tar(1) manpage does not point out the practical implications of the -H arguments at all; I think it would be very helpful if a search for a likely keyword ("nanosecond", "second", "resolution", etc.) led to the paragraph on -H.

Автор: vich Размещён: 16.03.2018 11:46
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