Problem about install logstash-input-plugins on linux

i type command: install logstash-input-3.3.0-java.gem
then back:

install: missing destination file operand after ‘logstash-input-3.3.0-java.gem’
Try 'install --help' for more information.

You need to be in the logstash bin directory to install plugin and by executing logstash-plugins file you can install plugin.

./logstash-plugin install /path/to/logstash-input-http-3.3.0-java.gem