The following five options are useful only when verifying checksums:¶

--ignore-missing

don't fail or report status for missing files

--quiet

don't print OK for each successfully verified file

--status

don't output anything, status code shows success

--strict

exit non-zero for improperly formatted checksum lines

-w, --warn

warn about improperly formatted checksum lines

--help

display this help and exit

--version

output version information and exit

The sums are computed as described in FIPS-180-2. When checking, the input should be a former output of this program. The default mode is to print a line with checksum, a space, a character indicating input mode ('*' for binary, ' ' for text or where binary is insignificant), and name for each FILE.