Visual Studio Code: How to actually search and replace a word in all files?

Visual Studio Code v 1.3.0++ has this feature:

Replace functionality can be accessed:

• In the Search View by expanding the Search textbox
• Using Ctrl + Shift + H, from the Edit | Replace in Files menu
• Using Replace in Files command in the Command Palette

VS Code also supports capturing groups when using regex, captured groups (using parenthesis) can be referenced with $1 for the first match, $2 the second etc. $0 returns the complete match.

Reversing "abc"

Appending "def"

It's currently not possible to replace in all files. The good news is it's part of the June Iteration Plan. The feature has already passed a couple of tests. So it will be probably released in July 2016.