How to copy without overwriting

[KIA]aze · 03-08-2007, 04:40 AM

How can I copy files without overwriting files in the destination directory AND without having to answer a prompt everytime.
(and also independently of wether the source file is older/newer than the destination file)

silent_ion · 03-08-2007, 05:11 AM

Maybe something like this:

Quote:

false | cp -i dir1/* dir2/ > /dev/null 2>&1

makyo · 03-08-2007, 06:43 AM

Hi.

Most Linux systems have utility rsync installed. This worked for me:

Code:

rsync -av --ignore-existing d1/ d2/

see man rysnc for details.

Another, somewhat more complex solution would be to write a script to compare file names in the two directories and omit the copy for matches ... cheers, makyo

[KIA]aze · 03-08-2007, 07:04 AM

Thanks it works perfectly.

But could you explain exactly how it works?

I understood how the pipe works, but I don't understand the difference between "2>1" and "2>&1".

Code:

$false | cp -irv toto toto2/ 2>1
`toto/newfile10' -> `toto2/toto/newfile10'

Code:

$false | cp -irv toto toto2/ 2>&1
cp: overwrite `toto2/toto/file'? cp: overwrite `toto2/toto/newfile'? cp: overwrite `toto2/toto/newfile2'? cp: overwrite `toto2/toto/newfile3'? cp: overwrite `toto2/toto/newfile4'? cp: overwrite `toto2/toto/newfile10'? `toto/newfile12' -> `toto2/toto/newfile12'

I know that 0=stdinput, 1=stdoutput, 2=stderr.
But why "&1" instead of "1"?

I also tried redirecting stdin to stdout to output "false", but instead it asked me for confirmation:

Code:

$false | cp -irv toto toto2/ 0>&1
cp: overwrite `toto2/toto/file'?

edit:
OK, I see, I just created some useless 0,1 and 2 files... ^^

[KIA]aze · 03-08-2007, 07:42 AM

Something else:

Is there a way to generate a nice error file of files that were not overwritten?
I tried 2>err of course, but the problem is that they all get listed in one line instead of one per line.