Copy files without losing file/folder permissions

You can make a tar archive of the source, copy that to the other computer using the USB drive, and extract it there. Tar preserves file permissions.

1 - On the source computer:

cd /path/to/folder/to/copy
tar cvpzf put_your_name_here.tar.gz .

2 - Copy put_your_name_here.tar.gz to the USB drive and then to the other computer

3 - On the destination computer:

cd /path/to/destination/folder
tar xpvzf put_your_name_here.tar.gz

tar will recreate the archived folder structure with all permissions intact.

Those commands will archive the contents of the source folder and then extract them into the destination folder. If you want to copy the folder itself, then you should, at step 1:

cd /path/to/parent/folder
tar cvpzf put_your_name_here.tar.gz folder_to_copy

The same mechanism could be used for single files.

If you can connect from one computer to the other using ssh, @siddharthart answer (rsync) might be more practical.

You could try rsync with -a flag to maintain all permissions while copying. I'm not aware of a simpler solution, but I had used it for a purpose in the past.

Rsync gives brilliant support to repeated copying, updating folders etc. while remaining blazingly fast.

I think taring and then untaring should work on both files and directories.

to tar:

tar cvpfz /target.tar.gz /source/

to untar:

tar xvpfz /source/

The p flag stands for --preserve-permissions.

You should see man tar for more info.