\ = backslash
\\ = two backslashes
\\\ = three backslashes
' = a single quote
'' = two single quotes
\' = a backslash and a single quote
" = a double quote
\" = a backslash and a double quote
'"' = a double quote within 2 single quotes

Here's a test of formatting and odd characters. 
This is the second line. 

Blank line above and some characters below:

< = less than
> = greater than
& = ampersand
&amp; = an ampersand, a-m-p and a semicolon
! = exclamation

##</code><code>##

$var = $dbh->quote( $var ); # I could also use placeholders