Reference
Every shortcut, in one place
Written in their macOS form. On Windows and Linux, ⌘ is Ctrl and the rest is the same.
Application
⌘+K
Search your whole vault
⌘+,
Open settings
⌘+\
Toggle sidebar
Editor — structure
⇥
Indent block
⇧+⇥
Outdent block
⇧+↵
Line break within block
↵
Split block / new block
Editor — insertion
⌘+.
Open Insert Picker
Editor — formatting
⌘+B
Bold
⌘+I
Italic
⌘+U
Underline
⌘+⇧+S
Strikethrough
Editor — history
⌘+Z
Undo
⌘+⇧+Z
Redo
Reader — annotations
⌘+H
Highlight selection in yellow
⌘+U
Underline selection in yellow
⌘+⇧+H
Highlight selection with recent colour
⌘+⇧+U
Underline selection with recent colour
Reader — navigation
⌘+F
Find in source
esc
Close the topmost reader overlay, or go back
The same list lives in Piper under Settings → Hotkeys. Rebinding is not available yet, so these are fixed for now.