Continue a directory tree checksum from a given file

I have: - A checksum.txt file which contains many lines of checksums of single files from a mountpoint in a huge directory, which mounted and then it disconnected, thereby not finishing the checksum.txt (partial checksums) - localchecksums.txt full checksum list, containing thousands of lines of SHA256 checksums with filenames etc. I would like to: - Compare the remote mount checksums and local ones with sha256sum -c checksum.txt localchecksum.txt or similar, but: 1. I don't want to go through gigabytes of data again to get the remaining hashes 2. I don't want to restart the whole process for checksum.txt I generated the list by using find to recursively find single files and exec sha256sum on them. It is possible to get the remaining hashes by comparing the two files or somehow continue checking the checksums by reading the checksum.txt file and only calculating checksums for unchecked files. The problem with the first approach is that the order is different in the files. The second approach sounds good but I don't have any idea how to start with that. #### Sample of any of the checksum files:

8e2931cc1ad3adc07df115456b36b0dbd6f80f675e0a9813e20ad732ae5d4515  ./folder/8ggSHp5I7hNEl3vDCbWv6Q/wA-KzXIh1Ce3G93s20X24v_4vUeywBe3mXPhGjPt_Lg/cRf8KgbqIsqwbon3DX3PN1-oV6_Nr9Baeymaw-ZJw00
37d2dfe2315cc401536329e3fbe421384bbb50c656c3dbeb42798e5666822e6c  ./folder/8ggSHp7I7hHEl3vDCbWv6Q/wA-KzXIh1Ce3G93s2oX24v_4vUeywBe3mXPhGjPt_Lg/V02s6HKhyJ9Nyd2jQtSjWg
d0e9b95065a264db0d372ccace5d3a72f38f74ca7b44da4794dae23c91e18e57  ./folder/8ggSHp7I7hNxl3vDCbWv6Q/wA-KzXIh1Ce3G93s2oX24v_4vUeywBe3mXPhGjPt_Lg/U3fhBugX6pexYzh6qGKlW7lYWsFShWH7JwN9fmU8ay2lLZkciH2sXsiGbmIc97iJ
44a5fe29063e472857bb9a1929af06a32bb4b2394630f80c2dc732fd662620bc  ./folder/8ggSHp7I7hNEc3vDCbWv6Q/wA-KzXIh1Ce3G93s2oX24v_4vUeywBe3mXPhGjPt_Lg/gTrqUL4ZjWTWMl6BcjfwUe5bBDatscwUoYY9IFQDztc