Another alternative is access Bundletool release page and download the bundletool-all-[LAST-VERSION].jar file into some directory.
After that you could run it on the directory calling:
java -jar bundletool-all-0.10.2.jar your_arguments_here
If you want, rename the jar file to bundletool.jar, then run it calling:
java -jar bundletool.jar your_arguments_here
If you don't want call java
every time, you can create an alias for that, and after that run quicly:
alias bundletool='java -jar bundletool-all.jar'
bundletool your_arguments_here