echo - print arguments

Echo writes its arguments separated by blanks and terminated by a newline on the standard output.  Option
       -n suppresses the newline.

       If  echo draws an error while writing to standard output, the exit status is Otherwise the exit status is
       empty.

                                                                                                    ECHO(1plan9)

       echo - print arguments

/src/cmd/echo.c

echo [ -n ] [ arg...  ]