You are take a full back up of the system to an external storage. The external storage is using a exFAT file system, so not all Linux file system information is going to be stored (information such as owner, group, and permissions for example will be lost since FAT file system does not support those). Once the copy operation is done you have to verify that absolutely all the files have been copied and are exactly the same. The data is a mix of text and binary data. How can you make sure the files are exactly the same, even if the time stamps are different.can use cmp command to compare the filescan use diff command to see if the files have any differencessince some timestamps and permission information maybe lost when copying to exFAT formatted filesystem, do a fschk on the external disk to verify its integrity.can do a echo $? to see what the exit status code for cp command was