Bash string manipulation

Summary: String Manipulation and Expanding Variables

${parameter:-defaultValue}	Get default shell variables value
${parameter:=defaultValue}	Set default shell variables value
${parameter:?"Error Message"}	Display an error message if parameter is not set
#var	Find the length of the string
var%pattern	Remove from shortest rear (end) pattern
var%%pattern	Remove from longest rear (end) pattern
var:num1:num2	Substring
var#pattern	Remove from shortest front pattern
var##pattern	Remove from longest front pattern
var/pattern/string	Find and replace (only replace first occurrence)
var//pattern/string	Find and replace all occurrences