If you put your checksum list file into the
same directory, you can get a failing checksum when you test it. Example:
Code:
$ mkdir /tmp/test && cd /tmp/test
$ touch a b c
$ sha256 * > SHA256
$ sha256 -C SHA256 *
(SHA256) SHA256: FAILED
(SHA256) a: OK
(SHA256) b: OK
(SHA256) c: OK
The checksum file is not static. It is changing contents after it is first tested as the files a b c are checksummed later.