Text Editor that hilights all instances of selection for Mac

Sublime Text is able to do that.

Who said BBEdit couldn't do it?

With your document in the front window:

• Choose Search > Live Search ⌥ ⌘ F
• Enter your search string
• Notice that all instances of that string are now highlighted in your document

To make Live Search go away, click the Done button.

Reference: BBEdit 9.5 User Manual, pages 159-160

TextMate 2 does this really nicely bound to control-W

This macro [1] is built in.

^W will select a word, but once a selection exists, ^W will add the next instance to the (mult-) selection: Really nice feature!

Even better: double tap the shift key to un-select the last-added instance (great if you overshoot the set you wanted to select.

Even better: All of these are now separate selections, so you can type edit select and it works on each separately, but synchronously. Fabulous time saver!

[1] It's just a macro bound to ^W with a dyn.selection Scope selector

(
    {   command = 'copySelectionToFindPboard:'; },
    {   command = 'findNextAndModifySelection:'; },
)