Gum automatically detects if the project is Gradle or Maven based and runs the appropriate command. However in the case that Gum guesses wrong you can force a specific build tool to be used.
Gum supports the following flags
-gc displays current configuration and quits
-gd displays debug information
-gg force Gradle build
-gh displays help information
-gj force jbang execution
-gm force Maven build
-gn executes nearest build file
-gq run gm in quiet mode
-gr do not replace goals/tasks
-gv displays version information
Gum will execute the build based on the root build file unless -gn is specified, in which case the nearest build file will be selected. If a specific build file is given (-b, --build-file for Gradle; -f, --file for Maven) then that file will be used instead.
For versions of Ubuntu between 14.04 LTS (Trusty Tahr) and 15.10 (Wily Werewolf), as well as Ubuntu flavours that don’t include snap by default, snap can be installed from the Ubuntu Software Centre by searching for snapd.
Alternatively, snapd can be installed from the command line:
sudo apt update
sudo apt install snapd
Either log out and back in again, or restart your system, to ensure snap’s paths are updated correctly.