Copy and verify a directory in Linux
 

Hello

I m transferring a folder from usb to local drive. I am using cp -r command to do it,
which works for me. But I want to verify if the file is transferred good.

I thought of 2 things - file size verification and CRC verification.

1, File size is different in usb drive and local drive - a few bytes different,
2. CRC verification is good.. but not sure how to do it..
I tried using cksum. is it OK to CRC a directory with cksum? If not, how i can
CRC all files in the directory?

3. Any other ideas?

thanks,
jis

Use 'sync' command to flush "temporary" data to disk. I always use this when transferring to USB devs.

Then, if you are paranoid, run md5sum on fileonpc vs fileonusb and see if the checksums are identical:
This is just a mockup, but if the two numbers are identical the files are identical.

But if I understand you correctly, it's just about knowing that the data has actually been written. In that case, the sync command is your friend.

Try to copy the files again, this time with rsync and the -c option. rsync will compare source and destination files based on a checksum before it copies and skip files that are the same in source and destination. So if rsync does not copy a file you can be sure that the copy is not corrupted.
Example:

You can use md5sum for generating and checking:

https://sourceforge.net/projects/crcsum/ has cp & mv with crc checksum