addcr — inserts a CR (\015) before each LF (\012)
addcr reads input from stdin and writes it to stdout. It inserts a CR (\015) before each LF (\012), i.e., at the end of each line of input. It does not insert a CR at the end of a partial final line.
the reverse of this filter
a wrapper for a command that performs CR insertion on its standard I/O