ANSI escape sequence for "Command" key?

I can't make sense of your question. ANSI escape sequences begin with the Esc character and end with an ANSI-specified terminating character. They do not recognize the Mac's Command key or the Alt key and they have nothing to do with the ^, ~, or $ characters, except possibly as sequence modifiers, but these are unrelated to "ctrl", "alt", and "shift".

Now, it's possible that a smart terminal or terminal emulator, e.g., Terminal, can be programmed to do what you want, but this would be specific to your terminal, which you did not specify.

I thought I understood bash fairly well, but I have no idea what you mean by saying you can emulate a Ctrl-C in a bash script with "^C". What would it do...interrupt the script that's running? Why not just execute "exit"?

Maybe an example of what you can do with "^C" would be helpful.

Hi Evan,
This is more than a failure of terminology. The use of certain key sequences cause the terminal to produce certain characters that are just like letters except that many processes take special action when these characters are encountered. These characters are called "control characters."

For instance, type <Control>-v to "tell the shell" to not take special action on the next character produced. Then, if you type <Control>-c, the terminal will produce an End-of-Text character, ANSII character 3, and the shell will accept it as a literal character. However, it has no symbol for that character so it displays a pair of characters, "^C", in its place. Internally though, there is no carat and no 'C'; there is only the number three, which is the ANSII code for the End-of-Text character.

The bash shell will substitute control characters for certain escape sequences in expanding words of the form $'string'. For instance, consider the following command:

echo $'\003' | cat -v
^C

Above, the first line is a command that you can cut-and-paste into your terminal. The second line is the output you would see if you execute the command. Bash replaces the $'\003' word with the literal control character and then "cat" converts that character to the pair of characters, "^C", to show you what had been there.

Of course there are still terminology problems; you are not using the word "emulate" correctly. However, if there was such a meaning, I think that one would say that the character sequences "emulate" the control character, not the other way around.

On the other hand, when you modify a key with the "Command" key, Macintosh programs treat that as an attempt to invoke a function of that program. No character is produced. In fact technically, the program never even sees the keystrokes. The system intercepts the key event and converts it to an AppleEvent.

One tool on Macs specializes in producing AppleEvents and that is AppleScript. Fortunately, Apple wrote a utility to grant the shell access to AppleScript and that is the "osascript" command. That allows you to sort of imbed AppleScript in a shell script and that would allow you to send any program any event that the system would generate in response to a command key sequence.
--
Gary
~~~~
"Home life as we understand it is no more natural to us
than a cage is to a cockatoo."
-- George Bernard Shaw

Of course, by "ANSII", Gary means ASCII. And, although 3 is technically the ASCII end-of-text character, it is rarely, if ever, used for this purpose.