Coreutils manpages tend to be short reference sheets listing the available
options. Further documentation is provided in the "info" command, as should
be mentioned as the end of each manpage.
From the docs:
`-b'
`--binary'
Treat each input file as binary, by reading it in binary mode and
outputting a `*' flag. This is the inverse of `--text'. On
systems like GNU that do not distinguish between binary and text
files, this option merely flags each input file as binary: the MD5
checksum is unaffected. This option is the default on systems
like MS-DOS that distinguish between binary and text files, except
for reading standard input when standard input is a terminal.
`-t'
`--text'
Treat each input file as text, by reading it in text mode and
outputting a ` ' flag. This is the inverse of `--binary'. This
option is the default on systems like GNU that do not distinguish
between binary and text files. On other systems, it is the
default for reading standard input when standard input is a
terminal.