Special characters and operators

$var -Variable



${var} -Same as $var



${var-default} -If $var is not set, use the string "Morjens"



${var=default} -If $var is not set, set it to default and use that value.





${var+instead} - If $var is set, use instead. Otherwise empty string.




${var?message} -If $var is not set, print message. If $var is set, use its value.