cp command doesn't overwrite, but creates new folder (second time, third, fourth, .. time it works)

Question

I use the following command to copy a folder (named 'dist') containing a react project to my frontend folder:

cd apps/react-app
sudo cp -R dist ../server/frontend/client

The first time I run the 'cp'-command, the content of the 'dist'-folder gets copied into the 'client'-folder. I would expect that when I run this command again, the cp-command would overwrite the files in the 'client'-folder. This doesn't happen, instead, the 'cp'-command now creates a 'dist'-folder inside the 'client'-folder en puts all the new files in there. The 3th, 4th, ... time I run the 'cp'-command, it overwrites all the files in the 'dist'-folder, but the files from the first 'cp'-command are still in the 'client'-folder also.

How can I cp the files from the 'dist'-folder to the 'client'-folder, and whenever I run this command again, it overwrites (instead of creating a new folder)?

Does the client directory already exist before all of this? — DonHolgo, Apr 27 '21 at 07:52

Pierre ALBARÈDE · Answer 1 · 2021-04-26T23:42:36.943

0

Yes, cp overwrites. It is idempotent.

The first time I run the 'cp'-command, the content of the 'dist'-folder gets copied into the 'client'-folder.

Are you sure? Normally, the folder itself should be copied (including its content), and indeed that is want you see in the next runs.

How can I cp the files from the 'dist'-folder to the 'client'-folder,

With

cp -r dist/* client

edited Apr 26 '21 at 23:42

answered Apr 26 '21 at 23:28

Pierre ALBARÈDE

149

1

cp is not naturally idempotent. You have to use cp -r dist/. client for it be so – Chris Davies Apr 26 '21 at 23:59
Actually you can't copy a directory without -r. – Pierre ALBARÈDE Apr 27 '21 at 00:21
Can you show an example? The original poster seems to have one but I doubt it. – Pierre ALBARÈDE Apr 27 '21 at 00:23
The OP's example is valid – Chris Davies Apr 27 '21 at 05:03
Yes, the content of the 'dist' folder is copied into the 'client' folder the first time, not the folder itself. The second time, a 'dist' folder shows up with all that content again. – Sam Leurs Apr 27 '21 at 10:29
I can't reproduce it. With zsh on my computer, cp -R always copy the folder, not its content. It is confusing, just like "drinking a glass of wine". – Pierre ALBARÈDE Apr 27 '21 at 11:14
You should provide a minimal complete example. – Pierre ALBARÈDE Apr 27 '21 at 11:16
OK I got it. This happens if and only if ../server/frontend/client does not exist before running cp. So if you run mkdir -p ../server/frontend/client before cp then no problem. – Pierre ALBARÈDE Apr 27 '21 at 11:21
And cp is not idempotent. – Pierre ALBARÈDE Apr 27 '21 at 11:27
As your question was really not well written, I suggest that you write a nice concluding answer. – Pierre ALBARÈDE Apr 27 '21 at 11:30
I realize that rsync -r does not have this strange behaviour of cp -r so you could use rsync -r instead of cp -r. – Pierre ALBARÈDE Apr 27 '21 at 11:33
I will write a conclusion in my question tomorrow. Thanks your all of your help! – Sam Leurs Apr 27 '21 at 18:25

cp command doesn't overwrite, but creates new folder (second time, third, fourth, .. time it works)

1 Answers1