String Manipulation and Expanding Variables

String Manipulation and Expanding Variables

For your ready references here are all your handy bash parameter substitution operators. Try them all; enhance your scripting skills like a pro:

${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
REFERENCES:

via http://www.cyberciti.biz/tips/bash-shell-parameter-substitution-2.html