Your heuristics are pretty bad. Here's what they find on a Debian wheezy machine of mine (I've manually marked correct hits with a
If you pick the first alphabetic match, it's a color calibrator.
Here's the list of alternatives for
x-terminal-emulator, which is the correct answer (as far as distribution-managed programs is concerned) on this Debian machine:
You're finding 7 out of 15 (accounting for vagaries of names), which isn't a very good hit rate.
You could try to refine your heuristics, but it's a never-ending game. The minimum would be to retain only executables that both link against some X11 libraries and call some master terminal function or utility like
grantpt, but that's bound to find a lot of spurious positives too, and to miss executables where the call is in a library (like
konsole). And this will miss native code executables that are accessed through a shell wrapper (there are several in my list).
Detecting whether a program is an X terminal emulator from the executable content is hopeless.
Detecting programs by name is a far better heuristic.
Note also that different programs have a different command line syntax. Most of them accept
-T TITLE and
-e COMMAND, but they have different parsing rules for
-e (going through a shell or not, taking multiple arguments or not) so you should pass a single parameter after
-e, not containing any shell special characters.
On Debian and derivatives,
x-terminal-emulator is guaranteed to be an X terminal emulator that supports
-e, such that
-e uses all subsequent command line parameters as a command and its argument and doesn't do shell expansion on them. Because some emulators behave differently,
x-terminal-emulator is sometimes a wrapper that takes a more xterm-like syntax (
xfce4-terminal.wrapper are two examples of this).
I don't know of anything like this on other unix variants. For anything like portability, a hard-coded list of program names is your best bet.
Furthermore, detecting installed terminal emulators won't give you any idea about the user's preferences. For example, if I use Gnome, I probably don't want your application to launch Konsole — unless I happen to prefer Konsole, but how would you know that?
The de facto standard for user preferences is via FreeDesktop.org specifications. Freedesktop publishes an
xdg-utils package which contains programs such as
xdg-open to open a document in the proper application,
xdg-email to launch the user's preferred email composing application, and more to the point
xdg-terminal to open the user's preferred terminal emulator.
This would make
xdg-terminal the right thing to use, and you should use it if it's there. Unfortunately,
xdg-terminal isn't available everywhere; for example, Debian doesn't ship it (it's a long-idle bug). Furthermore
xdg-terminal allows a single command argument, and is not consistent about what kind of expansion this argument undergoes.
Whatever you do, make sure to provide an easy way for the caller to specify a preference. Even
xdg-terminal doesn't always get it right.
Thus your best strategy is:
- if the user has specified a preference, use it
- else try
- else try
- else try a hard-coded list