\a  alert (bell)  \b  backspace
\e  an escape character  \f  form feed
\n  newline  \r  carriage return
\t  horizontal tab  \v  vertical tab
\\  backslash  \`  single quote
\nnn  octal value of characters ( see [http://www.asciitable.com/ ASCII table] )  

\xnn  hexadecimal value of characters ( see [http://www.asciitable.com/ ASCII table] )

echo $'web: www.linuxconfig.org\nemail: web\x40linuxconfig\56org'