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.
