I have been an avid Textmate user since about 5 years ago. I have worked with it for so long that I have been so familiar with it. In the past few months I have been trying out Atom. Atom is an open-source editor created by Github. I always say that an editor is only as good as how you use it. Shortcuts are one of the ways to enhance speed with coding.
Here is a comprehensive shortcut list used in Atom
Atom Editor Shortcuts
|convert to lowercase||Command-k-L|
|convert to uppercase||Command-k-U|
|Toggle Tree View Pane||Command-\|
|Reopen Last File||Command-Shift-t|