Tidying up buffers
Sometimes you want to close several buffers and not just the current buffer with
SPC b d.
SPC b b displays a list of open buffers in a popup window.
M-SPC opens the Helm transient menu on the buffer popup window, allowing you to navigate using
M-D will prompt you to kill the buffer the cursor is currently on.
t will mark the buffer the cursor is currently on.
T will mark all buffers listed in the popup.
M-D will prompt you in turn to delete all the marked buffers.
There are a range of actions you can run from the Helm transient state or even when you just have the buffer list popup open.
a switches to the actions page
C-z displays list of available actions for a buffer
Helm Transient state menu
M-SPC to open Helm transient state menu, simplifying the keybindings for tidying up lots of buffers.
Gnome Desktop keybinding conflict
M-SPC is used by the Gnome desktop for the window menu, so recommend you change the Gnome keyboard settings to use a different binding, i.e.