Merge pull request #526 from pamarcos/appimage-help

Add --appimage-help option

Author: TheAssassin

Diff for: README.md

@@ -62,6 +62,7 @@ Running an AppImage mounts the filesystem image and transparently runs the conta
 
 If you invoke an AppImage built with a recent version of AppImageKit with one of these special command line arguments, then the AppImage will behave differently:
 
+- `--appimage-help` prints the help options
 - `--appimage-offset` prints the offset at which the embedded filesystem image starts, and then exits. This is useful in case you would like to loop-mount the filesystem image using the `mount -o loop,offset=...` command 
 - `--appimage-extract` extracts the contents from the embedded filesystem image, then exits. This is useful if you are using an AppImage on a system on which FUSE is not available
 - `--appimage-mount` mounts the embedded filesystem image and prints the mount point, then waits until it is killed. This is useful if you would like to inspect the contents of an AppImage without executing the contained payload application

Diff for: runtime.c

@@ -204,6 +204,20 @@ mkdir_p(const char *path)
     return 0;
 }
 
+void
+print_help()
+{
+    printf("AppImage Options:\n\n"
+           "--appimage-help                 Prints this help\n"
+           "--appimage-offset               Prints the offset at which the embedded filesystem image starts, and then exits\n"
+           "--appimage-extract              Extracts the contents from the embedded filesystem image, then exit\n"
+           "--appimage-mount                Mounts the embedded filesystem image and prints the mount point, then waits until it is killed\n"
+           "--appimage-version              Prints the version of AppImageKit, then exits\n"
+           "--appimage-updateinformation    Prints the update information embedded into the AppImage, then exits\n"
+           "--appimage-signature            Prints the digital signature embedded into the AppImage, then exits\n"
+           );
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -228,8 +242,15 @@ main (int argc, char *argv[])
 
     fs_offset = get_elf_size(appimage_path);
 
-    /* Just print the offset and then exit */
     arg=getArg(argc,argv,'-');
+
+    /* Print the help and then exit */
+    if(arg && strcmp(arg,"appimage-help")==0) {
+        print_help();
+        exit(0);
+    }
+
+    /* Just print the offset and then exit */
     if(arg && strcmp(arg,"appimage-offset")==0) {
         printf("%lu\n", fs_offset);
         exit(0);