sed Insert a Newline Into the RHS of a Substitution last updated December 14, 2008 in Categories AIX, BASH Shell, CentOS, Debian / Ubuntu, Linux, UNIXQ. How do I insert a newline into the RHS of a substitution using sed under Linux / UNIX like operating systems? My line pattern is as follows:This is a test. This is another input.I’d like to insert a newline after dot (.).