The quick answer is: It depends on your init system.

The long answer is: For current versions of Ubuntu, you probably have a mix of Upstart, and SystemV. Newer versions of Ubuntu after 15.04 "Vivid Vervet" (and other Linux distros like RHEL/CentOS 7) are moving to use SystemD.

Upstart

• Upstart Documentation

To list all services:

initctl list

To list all Upstart services and run initctl show-config on them, this one-liner may be helpful:

initctl list | awk '{ print $1 }' | xargs -n1 initctl show-config

System V

• SysV Runlevels Documentation

To list all services:

service --status-all

OR:

# for init scripts:

ls /etc/init.d/



# for runlevel symlinks:

ls /etc/rc*.d/

SystemD

• SystemD for Upstart Users


• FedoraProject SystemD Documentation


• RHEL 7: Managing Services with SystemD


• RedHat: SystemD Overview

To list all services:

systemctl list-unit-files --type=service

OR:

ls /lib/systemd/system/*.service /etc/systemd/system/*.service

The /etc/init.d and /etc/rc.* directories have been superseded by the 'upstart' init tool. Although scripts in these directories will be executed as expected, the new method for running things on init is defined by files in /etc/init/

You can list all of the upstart jobs with by querying upstart over dbus:

dbus-send --print-reply --system --dest=com.ubuntu.Upstart 

        /com/ubuntu/Upstart com.ubuntu.Upstart0_6.GetAllJobs

You may have to change 0_6 to reflect the version of upstart you have. This command works on my lucid install.

If you want a nice graphical representation of services and time it takes to boot try:

apt-get install bootchart

Id use initctl show-config <servicename> to really get the details of when/if your service will start during boot.

Like so:

$ initctl show-config myservice

myservice

  start on runlevel [2345]

  stop on runlevel [!2345]

Or for NFS4 idmap-daemon:

$ initctl show-config idmapd

idmapd

  start on (local-filesystems or mounting TYPE=nfs4)

  stop on runlevel [06]

chkconfig is only preferable on RedHat based systems imho.

On 12.04 we could use:

sudo apt-get install chkconfig

chkconfig --list

but it was removed in 12.10.

Sample output:

acpi-support              0:off  1:off  2:on   3:on   4:on   5:on   6:off

acpid                     0:off  1:off  2:off  3:off  4:off  5:off  6:off

apparmor                  0:off  1:off  2:off  3:off  4:off  5:off  6:off  S:on

Besides system services and scripts under:

/etc/init.d/
/lib/systemd/system/
/etc/systemd/system/

There are probably AutoStart Applications too, for example:

find / -name "*autostart*"



ls -1 "/etc/xdg/autostart" "/home/$USER/.config/autostart" "/usr/share/gdm/autostart"  "/usr/share/gnome/autostart"

Using gawk:

ls -l /etc/rc*.d/* | gawk 'match($0, /rc([0-6S]).d.*/(.*)$/, a) {l[a[2]]=l[a[2]]a[1]","}; END{for(v in l){print v,substr(l[v],1,length(l[v])-1)}}'

Sample output:

$ ls -l /etc/rc*.d/* | gawk 'match($0, /rc([0-6S]).d.*/(.*)$/, a) {l[a[2]]=l[a[2]]a[1]","}; END{for(v in l){print v,substr(l[v],1,length(l[v])-1)}}' | egrep README

README 0,1,2,3,4,5,6,S