When you press
Space (SPC) in Spacemacs, it shows this window with all commands you can execute.
And they are grouped by categories. For example
SPC p for the project’s commands,
SPC f for the file’s commands.
So you can press
SPC f s to save file or
SPC p c to compile project.
It’s similar to Command Palette Ctrl-Shift-P but instead of searching you can execute command by pressing couple of keys
In Atom it could look like this - you press
Ctrl-Alt-P to open similar window and then just press
f s to save a file