The specification for "pr" is as specified in the SUS but with the following differences as listed below.
This option as specified in the SUS is not supported
use hat notation (^G) and octal backslash notation.
merge full lines, turns off -W line truncation, no column alignment.
start counting with NUMBER at 1st line of first page printed.
separate columns by an optional STRING, don't use -S "STRING", -S only: No separator used without -S.
omit page headers and trailers, eliminate any pagination by form feeds set in input files.
use octal backslash notation
set page width to PAGE_WIDTH (72) characters always, truncate lines, except -J option is set, no interference with -S or -s.
display this help and exit
output version information and exit