If you take a look at the online help in nano (Ctrl+G) you'll be presented with a list of the commands available. For your convenience, I've duplicated that list below; the ones I think are most important are marked with three asterisks. If you would like to read a short tutorial on how to use the nano editor, be sure to visit the nano tutorial page!
Many of you will probably be aware of pico, the lightweight text-editor that comes with OS X. While there are very powerful text editors available, such as emacs and vi, pico still remains a great editor for simple text editing and beginning programmers, due to its intuitive interface. In the Terminal app on your Mac, invoke a command-line editor by typing the name of the editor, followed by a space and then the name of the file you want to open. If you want to create a new file, type the editor name, followed by a space and the pathname of the file. Here’s an example of using nano to open a new file named “myFile.conf” in your Documents folder.

Notepad Notepad is a free source code editor and Notepad replacement that supports several. Nov 19, 2019.
NOTE: Any command prefixed with a caret symbol (^) means to use the Ctrl key (e.g., ^G means to press the Ctrl+G keys at the same time). Any command prefixed with the letter M means to press the Alt key (e.g., M-R means to press the Alt+R keys together).
Most Helpful!  | Ctrl Key Combination  | Function Key  | Alt Key Combination  | Description  | 
***  | ^G  | F1  | Display the help text  | |
***  | ^X  | F2  | Close the current file buffer / Exit from nano  | |
***  | ^O  | F3  | Write the current file to disk  | |
^J  | F4  | Justify the current paragraph  | ||
^R  | F5  | Insert another file into the current one  | ||
***  | ^W  | F6  | Search for a string or a regular expression  | |
***  | ^Y  | F7  | Move to the previous screen  | |
***  | ^V  | F8  | Move to the next screen  | |
***  | ^K  | F9  | Cut the current line and store it in the cutbuffer  | |
***  | ^U  | F10  | Uncut from the cutbuffer into the current line  | |
***  | ^C  | F11  | Display the position of the cursor  | |
^T  | F12  | Invoke the spell checker, if available  | ||
***  | ^_  | F13  | M-G  | Go to line and column number  | 
***  | ^  | F14  | M-R  | Replace a string or a regular expression  | 
^^  | F15  | M-A  | Mark text at the cursor position  | |
***  | F16  | M-W  | Repeat last search  | |
***  | M-^ or M-6  | Copy the current line and store it in the cutbuffer  | ||
M-}  | Indent the current line  | |||
M-{  | Unindent the current line  | |||
^F  | Move forward one character  | |||
^B  | Move back one character  | |||
^Space  | Move forward one word  | |||
M-Space  | Move back one word  | |||
***  | ^P  | Move to the previous line  | ||
***  | ^N  | Move to the next line  | ||
***  | ^A  | Move to the beginning of the current line  | ||
***  | ^E  | Move to the end of the current line  | ||
M-( or M-9  | Move to the beginning of the current paragraph  | |||
M-) or M-0  | Move to the end of the current paragraph  | |||
M- or M-|  | Move to the first line of the file  | |||
M-/ or M-?  | Move to the last line of the file  | |||
***  | M-]  | Move to the matching bracket  | ||
M-- or M-_  | Scroll up one line without scrolling the cursor  | |||
M-+ or M-=  | Scroll down one line without scrolling the cursor  | |||
***  | M-< or M-,  | Switch to the previous file buffer  | ||
***  | M-> or M-.  | Switch to the next file buffer  | ||
M-V  | Insert the next keystroke verbatim  | |||
^I  | Insert a tab at the cursor position  | |||
^M  | Insert a newline at the cursor position  | |||
^D  | Delete the character under the cursor  | |||
^H  | Delete the character to the left of the cursor  | |||
M-T  | Cut from the cursor position to the end of the file  | |||
M-J  | Justify the entire file  | |||
M-D  | Count the number of words, lines, and characters  | |||
***  | ^L  | Refresh (redraw) the current screen  | ||
M-X  | Help mode enable/disable  | |||
***  | M-C  | Constant cursor position display enable/disable  | ||
M-O  | Use of one more line for editing enable/disable  | |||
M-S  | Smooth scrolling enable/disable  | |||
M-P  | Whitespace display enable/disable  | |||
M-Y  | Color syntax highlighting enable/disable  | |||
M-H  | Smart home key enable/disable  | |||
***  | M-I  | Auto indent enable/disable  | ||
M-K  | Cut to end enable/disable  | |||
M-L  | Long line wrapping enable/disable  | |||
M-Q  | Conversion of typed tabs to spaces enable/disable  | |||
M-B  | Backup files enable/disable  | |||
M-F  | Multiple file buffers enable/disable  | |||
M-M  | Mouse support enable/disable  | |||
M-N  | No conversion from DOS/Mac format enable/disable  | |||
M-Z  | Suspension enable/disable  | 
