Copying a file only when it is newer than the destination

Question

How do I copy a file in Linux only when the file being copied is newer than the version at the destination?

If the file at the destination is newer, I want the file copy to not go ahead.

Dennis · Answer 1 · 2011-09-29 15:30:24Z

up vote 0 down vote accepted

Using the update option (-u) with cp should do it for you.

answered Sep 29 '11 at 15:30

Dennis
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	thanks, it works for me – Eli Sep 29 '11 at 15:37
	Don't forget that voting and accepting answers (once you find the most useful) is what drives the site. – Dennis Sep 29 '11 at 15:50

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Kusalananda · Answer 2 · 2011-09-29 15:27:11Z

up vote 0 down vote

You're not saying what shell you're using, so I'm going to assume ksh:

if [[ file1 -nt file2 ]]; then cp file1 file2; fi

answered Sep 29 '11 at 15:27

	Isn't bash most common? – Rob Sep 29 '11 at 16:58
	@Rob, yes. This works in bash too, obviously. I just didn't have bash (or any standard Linux box) at hand when I wrote it. – Kusalananda Sep 29 '11 at 23:12

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2 Answers