Wp plugin is-installed (WP-CLI)

$ wp help plugin is-installed

NAME

  wp plugin is-installed

DESCRIPTION

  Checks if a given plugin is installed.

SYNOPSIS

  wp plugin is-installed <plugin>

  Returns exit code 0 when installed, 1 when uninstalled.

OPTIONS

  <plugin>
    The plugin to check.

EXAMPLES

    # Check whether plugin is installed; exit status 0 if installed, otherwise 1
    $ wp plugin is-installed hello
    $ echo $?
    1