Hi Lance,
You do have an option in MATLAB editor too to select similar words and then replace them to another word. However, it is only applicable if you choose to replace all of the similar words or a single one of them. To select specific instances of a variable and rename them, you would have to manually find and replace each instance of the variable that you want to rename. The following steps are for finding and replacing text in the current file.
Firstly, enter the command:
on the keyboard and then a small bar like below appears on top of the code.
You can enter the word that you want to search for and then expand the options by clicking on the arrow button next to "Find" to see:
(You can alternatively enter Ctrl + H if you want to open "Find" and "Replace" options at once).
When "Replace All" is clicked, the editor changes all the occurences of "dirName" to "directoryName". You can also replace words one-by-one by clicking on the "Replace" button.
You can choose if the word entered may be a part of another word or not, if the case has to be matched or not, or enter a regular expression to find and replace patterns of text, by using the options above the "Replace All" button.
Please take a look at this link for more information. 
