Continue aborted cp

Question

Is it possible to run cp again after it was aborted and make it start where it ended last time (not overwrite data that's already copied, only copy what's still left)?

Solution 1

It's cases like this that have taught me to use rsync from the start. However in your case, you can use rsync now. It will only copy new data across, including if cp stopped half way through a big file.

You can use it just like cp, like this:

rsync --append /where/your/copying/from /where/you/want/to/copy

Solution 2

In case the aborted cp was a recursive copy, you might want to resume with rsync including the option --recursive.

Example

Aborted copy command:

cp -r source-directory destination-directory

Let us assume that destination-directory already existed, so that this copy command created a directory named source-directory within destination-directory. This can be resumed via:

rsync --recursive --append source-directory destination-directory

Note that trailing slashes have a precise meaning in rsync path options.

In this case, the copy command could have gotten the argument source-directory or source-directory/, it does not make a difference. In the rsync command, however, it must be source-directory without trailing slash.

Solution 3

Use the -u switch, and see the cp man page.

Solution 4

rsync is a great tool also: man page at -> http://www.manpagez.com/man/1/rsync/

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Comments

[Phil]

but source files didn't changed or anything

[ericslaw]

the -u is for 'update' only... ie: it wont overwrite the existing files in the destination if they are same or newer...

[Araejay]

If you use -u, then it will copy the same big file again. -u only helps if you're trying to resume a large recursive copy.

[Zaz]

Or --append-verify to compare checksums at the end just to be sure.

[msa]

This answer was helpful for me because in my case it was many small-ish files and no problem to just delete the incomplete files before running my initial cp -a as cp -au again.

[Qin Heyang]

Should I be worried about unfinished files from the previous cp? Or the -u will take care of that?