nano

Ctrl+G Get Help
Ctrl+C Display the position of the cursor
Ctrl+O Write Out, Write the current file to disk
Ctrl+X Exit
Ctrl+K Cut the current line and store it in the cutbuffer
Ctrl+U Paste from the cutbuffer into the current line
Ctrl+W Search for a string or a regular expression
Alt+W  Repeat last search
Ctrl+Y Prev Page
Ctrl+V Next Page

Alt+U Undo the last operation
Alt+E Redo the last undone operation
Alt+Shift+} Indent Text
Alt+Shift+{ Unindent Text
Alt+M Mouse support enable/disable
Alt+X Help mode enable/disable
Alt+$ Soft wrapping of overlong lines enable/disable
Alt+P Whitespace display enable/disable
Alt+Y Color syntax highlighting enable/disable
Alt+D Count the number of words, lines, and characters