ive-file-in-a-controlled-way
$ sha256sum Test_02_Copy.zip
399a06c70562a9f8876ab13154c27063927ba8cb46df947e793104d1881fea95 Test_02_Copy.zip
$ dd if=/dev/urandom of=Test_02_Copy.zip bs=1 count=1 seek=100 conv=notrunc
1+0 records in
1+0 records out
1 byte copied, 5.2956e-05 s, 18.9 kB/s
$ sha256sum Test_02_Copy.zip
ba47b1e44fe757deabcdfc35a930dc72726a594aeb600ef1a1743598af44e17b Test_02_Copy.zip