The specification for "cat" is as specified in the SUS but with the following differences as listed below.
equivalent to -vET
number nonblank output lines.
equivalent to -vE.
display $ at end of each line.
number all output lines.
never more than one single blank line.
equivalent to -vT.
display TAB characters as ^I.
unlike as specified in the SUS, this option is silently ignored.
use ^ and M- notation, except for LFD and TAB.
output version information and exit.