How can I detect Gnome Terminal?

Question

I am writing a console application which makes use of the F1 key (for help). Unfortunately, while Konsole (of KDE) doesn't use this key, Gnome Terminal does, so the F1 key becomes inaccessible to my application. I don't think there's a way to detect whether the F1 key is already mapped in the GUI side of things (Gnome Terminal), but if there is, the answer to that will obviate this question. :)

Ergo, my next best bet is to try to detect whether I am running inside Gnome Terminal. Is there some way to do that? I'm primarily interested in gleaning this from within Ruby, but if it can be done via shell or environment variables, or virtual filesystem (/proc, /dev, etc.) then that will suffice.

I'm hoping for a reliable way to do this, but I can settle for "best guess" approaches like grepping the environment variables for clues that can let me reasonably assume that Gnome Terminal is the wrapping terminal.

Extra info: other keys are also "stolen" by Gnome Terminal. I intend to display some sort of informative message about alternative keys for Gnome users.

Answer 1

Googleage has revealed that I might be able to rely on Gnome Terminal setting the COLORTERM environment variable to 'gnome-terminal'.

Answer 2

For zsh:

[[ "$COLORTERM" == "gnome-terminal" ]] || [[ ${$(ps -p $(ps -p $$ -o ppid=) -o cmd=):t} == gnome-terminal* ]]

gnome-terminal used to set $COLORTERM, but this has been dropped (in 3.12.0-67-g1d5c1b6).

Answer 3

Normally you use termcap info aka terminfo. This tells you what kind of terminal you're working with and also what the keys are.

It is the user's choice, and since Gnome Terminal reports itself as probably a kind of x-term, as Konsole likely does, there is likely a way for the user to create an F1 keypress. Therefore, I suspect that the terminal capabilities of the two will be reported as equivalent.

This investigation of Function Key Escape Codes might be interesting to you without actually explaining how, if it is even possible, that the gnome terminal could be made to produce an F1 press. Thinking of the Mac OS X terminal I used a long time back, it caught PageUp and PageDown for the scroll bar, while Command-PageUp and Command-PageDown passed them through to the terminal.

Answer 4

A rather crude method, if you feel like delegating this to the shell -- otherwise, in C or C++, you will have to wade through your /proc, if you have one:

ps x | grep `ps o ppid,fname | grep bash | grep -v grep | head -1 | awk '{print $1}'` | grep 'gnome-terminal' | wc -l

If running from your own program, through system() for instance, you may with to 'grep' your program's name rather than 'bash'

I know, it's definitely "hack like a pirate" ;)

Answer 5

fwiw, this is a setting in gnome-terminal; users can go to Edit -> Keyboard Shortcuts in the gnome-terminal menus and change or delete the F1 keybinding.

Answer 6

I simply check the $TERM for the terminal emulator of my choice and then add an alias for spawning a new terminal in the current directory.

if [[ $TERM == 'xterm' ]] ; then
  alias nw='gnome-terminal --working-directory=$PWD'
fi