ジェンキンスを始めるには？

Ubuntu 16.04を使用しています。私のJavaはここにあります

which java
/usr/bin/java

Next
cat /etc/init.d/jenkins
#!/bin/bash
# /etc/init.d/jenkins
# debian-compatible jenkins startup script.
# Amelia A Lewis <[email protected]>
#
### BEGIN INIT INFO
# Provides:          jenkins
# Required-Start:    $remote_fs $syslog $network
# Required-Stop:     $remote_fs $syslog $network
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Start Jenkins at boot time
# Description:       Controls Jenkins Automation Server
### END INIT INFO

PATH=/bin:/usr/bin:/sbin:/usr/sbin

DESC="Jenkins Automation Server"
NAME=jenkins
SCRIPTNAME=/etc/init.d/$NAME

Jenkinsを起動する方法は混乱しています。コマンドラインから

jenkins
jenkins: command not found

ジェンキンスの現状

sudo service jenkins status
● jenkins.service - LSB: Start Jenkins at boot time
   Loaded: loaded (/etc/init.d/jenkins; bad; vendor preset: enabled)
   Active: active (exited) since Thu 2017-06-01 12:41:37 CEST; 29min ago
     Docs: man:systemd-sysv-generator(8)

Jun 01 12:41:36 milenko-System-Product-Name systemd[1]: Starting LSB: Start Jenkins at boot time...
Jun 01 12:41:36 milenko-System-Product-Name jenkins[6944]:  * Starting Jenkins Automation Server jenkins
Jun 01 12:41:36 milenko-System-Product-Name su[6962]: Successful su for jenkins by root
Jun 01 12:41:36 milenko-System-Product-Name su[6962]: + ??? root:jenkins
Jun 01 12:41:36 milenko-System-Product-Name su[6962]: pam_unix(su:session): session opened for user jenkins by (uid=0)
Jun 01 12:41:37 milenko-System-Product-Name jenkins[6944]:    ...done.
Jun 01 12:41:37 milenko-System-Product-Name systemd[1]: Started LSB: Start Jenkins at boot time.
Jun 01 13:10:00 milenko-System-Product-Name systemd[1]: Started LSB: Start Jenkins at boot time.

なぜ？