Simple utility that uses Launch Services to see what applications would be interested in editing a given file.

launchHandler.m

@import Foundation;
@import CoreServices;

// clang -g -fobjc-arc -fmodules launchHandler.m -o launchHandler

int main (int argc, const char *argv[]) {
    
    // Rudimentary argument checking.
    if (argc != 2) {
        printf ("usage: %s filename\n", argv[0]);
        return -1;
    }

    const char *filename = argv[1];

    // Get a string of the full path of the file, using realpath() as the workhorse
    char pathbuffer[MAXPATHLEN];
    char *fullpath = realpath (filename, pathbuffer);
    if (fullpath == NULL) {
        fprintf (stderr, "could not find %s\n", filename);
        return -1;
    }

    NSURL *url = [NSURL fileURLWithPath: @( fullpath )];

    // Ask launch services for the different apps that it thinks could edit this file.
    // This is usually a more useful list than what can view the file.
    LSRolesMask roles = kLSRolesEditor;
    CFArrayRef urls = LSCopyApplicationURLsForURL((__bridge CFURLRef)url, roles);
    NSArray *appUrls = CFBridgingRelease(urls);

    // Extract the app names and sort them for prettiness.
    NSMutableArray *appNames = [NSMutableArray arrayWithCapacity: appUrls.count];

    for (NSURL *url in appUrls) {
        [appNames addObject: url.lastPathComponent];
    }
    [appNames sortUsingSelector: @selector(compare:)];

    // Finally emit to the user.
    for (NSString *appName in appNames) {
        printf ("%s\n", appName.UTF8String);
    }

    return 0;

} // main