You can yank/paste bytes in visual mode using the y and Y key bindings which are aliases for y and yy commands of command-line interface. These commands operate on an internal buffer which stores copies of bytes taken starting from the current seek position. You can write this buffer back to different seek position using yy command:
[0x00000000]> y?
|Usage: y[ptxy] [len] [[@]addr]
| y show yank buffer information (srcoff len bytes)
| y 16 copy 16 bytes into clipboard
| y 16 0x200 copy 16 bytes into clipboard from 0x200
| y 16 @ 0x200 copy 16 bytes into clipboard from 0x200
| yp print contents of clipboard
| yx print contents of clipboard in hexadecimal
| yt 64 0x200 copy 64 bytes from current seek to 0x200
| yf 64 0x200 file copy 64 bytes from 0x200 from file (opens w/ io), use -1 for all bytes
| yfa file copy copy all bytes from from file (opens w/ io)
| yy 0x3344 paste clipboard
Sample session:
[0x00000000]> s 0x100 ; seek at 0x100
[0x00000100]> y 100 ; yanks 100 bytes from here
[0x00000200]> s 0x200 ; seek 0x200
[0x00000200]> yy ; pastes 100 bytes
You can perform a yank and paste in a single line by just using the yt command (yank-to). The syntax is as follows:
[0x4A13B8C0]> x
offset 0 1 2 3 4 5 6 7 8 9 A B 0123456789AB
0x4A13B8C0, 89e0 e839 0700 0089 c7e8 e2ff ...9........
0x4A13B8CC, ffff 81c3 eea6 0100 8b83 08ff ............
0x4A13B8D8, ffff 5a8d 2484 29c2 ..Z.$.).
[0x4A13B8C0]> yt 8 0x4A13B8CC @ 0x4A13B8C0
[0x4A13B8C0]> x
offset 0 1 2 3 4 5 6 7 8 9 A B 0123456789AB
0x4A13B8C0, 89e0 e839 0700 0089 c7e8 e2ff ...9........
0x4A13B8CC, 89e0 e839 0700 0089 8b83 08ff ...9........
0x4A13B8D8, ffff 5a8d 2484 29c2 ..Z.$.).