renice 19 -p $$ > /dev/null 2>&1
Use tar + xz to save extra metadata about the file(s), even if it is only 1 file.
tar cf - ~/test_files/* | xz -9ec -T0 > ./test.tar.xz
sha256sum ~/test_files/* | sort -n > ~/test_files/.sha256
Use tar + xz to save extra metadata about the file(s), even if it is only 1 file.
If that (or the extra options in tar for xattrs) is not enough, then create a checksum manifest, always sorted. Then use the above command to compress it all into a .tar file that now contains your checksum manifest. then ...