Overview of nano's shortcuts      

The editor's keystrokes and their functions         

File handling
Ctrl+S   Save current file
Ctrl+OOffer to write file ("Save as")
Ctrl+RInsert a file into current one
Ctrl+XClose buffer, exit from nano

Ctrl+K   Cut current line into cutbuffer
Alt+6Copy current line into cutbuffer
Ctrl+UPaste contents of cutbuffer
Alt+TCut until end of buffer
Ctrl+]Complete current word
Alt+3Comment/uncomment line/region
Alt+UUndo last action
Alt+ERedo last undone action

Search and replace
Ctrl+Q   Start backward search
Ctrl+WStart forward search
Alt+QFind next occurrence backward
Alt+WFind next occurrence forward
Alt+RStart a replacing session

Ctrl+HDelete character before cursor      
Ctrl+DDelete character under cursor
Alt+BspDelete word to the left
Ctrl+Del   Delete word to the right
Alt+DelDelete current line

Ctrl+T   Execute some command
Ctrl+JJustify paragraph or region
Alt+JJustify entire buffer
Alt+BRun a syntax check
Alt+FRun a formatter/fixer/arranger
Alt+:Start/stop recording of macro
Alt+;Replay macro

Moving around
Ctrl+B   One character backward
Ctrl+FOne character forward
Ctrl+One word backward
Ctrl+One word forward
Ctrl+ATo start of line
Ctrl+ETo end of line
Ctrl+POne line up
Ctrl+NOne line down
Ctrl+To previous block
Ctrl+To next block
Ctrl+YOne page up
Ctrl+VOne page down
Alt+\To top of buffer
Alt+/To end of buffer

Special movement
Alt+G    Go to specified line
Alt+]Go to complementary bracket
Alt+Scroll viewport up
Alt+Scroll viewport down
Alt+<Switch to preceding buffer
Alt+>Switch to succeeding buffer

Ctrl+C   Report cursor position
Alt+DReport line/word/character count
Ctrl+GDisplay help text

Alt+ATurn the mark on/off
TabIndent marked region
Shift+Tab   Unindent marked region
Alt+VEnter next keystroke verbatim
Alt+NTurn line numbers on/off
Alt+PTurn visible whitespace on/off
Alt+XHide or unhide the help lines
Ctrl+LRefresh the screen