echo [ -neE ] [ arg ... ]
       Write each arg on the standard output, with a space separating
       each one.  If the -n flag is not present, print a newline at the
       end.  echo recognizes the following escape sequences:

       \a     bell character
       \b     backspace
       \c     suppress subsequent characters and final newline
       \e     escape
       \f     form feed
       \n     linefeed (newline)
       \r     carriage return
       \t     horizontal tab
       \v     vertical tab
       \\     backslash
       \0NNN  character code in octal
       \xNN   character code in hexadecimal
       \uNNNN unicode character code in hexadecimal
       \UNNNNNNNN
              unicode character code in hexadecimal

       The -E flag, or the BSD_ECHO option, can be used to disable these
       escape sequences.  In the latter case, -e flag can be used to
       enable them.

       Note that for standards compliance a double dash does not
       terminate option processing; instead, it is printed directly.
       However, a single dash does terminate option processing, so the
       first dash, possibly following options, is not printed, but
       everything following it is printed as an argument.  The single
       dash behaviour is different from other shells.  For a more
       portable way of printing text, see printf, and for a more
       controllable way of printing text within zsh, see print.
