The reason I would like to do so (searched but found no specific info), is to eliminate the clutter of useless files. Bad idea? I hope not!
Let me clarify: I did find this: “sudo apt-get purge --auto-remove module-init-tools” but will that really get rid of System V?
What exactly is bothering you? Could you give a specific directory or list of files?
Akito, I’m just trying to purge files that are redundant to the functioning of systemd: simplification is the end. It may not be possible, due to 16.04…Perhaps it’s time to upgrade to 18.04 if systemd rules the roost there?
Running purge “upstart-sysv sysvinit-utils” gave a gnarly warning after a long listing of files, so I meekly said “no, don’t do it.”
Many of those files (e.g. /etc/init.d/ /etc/rc3.d) are created by SystemD as an “aide” to those used to SysV init… they’re tiny files, I wouldn’t lose any sleep about them, they’re hardly likely to use up your filesystem (or inode count)… different Linux’s do different things… Ubuntu/Debian still seem to use /etc/init.d/ /etc/rc3.d /etc/rc5.d - but RedHat 7.7 (?) and family no longer create files - here’s a RHEL 7.7 server I built recently for a customer (everything controlled via systemd) :
[[redacted]@[redacted] ~]$ ls -al /etc/init.d/
total 44
drwxr-xr-x. 2 root root 83 Dec 9 09:18 .
drwxr-xr-x. 10 root root 127 Mar 29 2019 ..
-rw-r--r--. 1 root root 18281 Mar 29 2019 functions
-rwxr-xr-x. 1 root root 4569 Mar 29 2019 netconsole
-rwxr-xr-x. 1 root root 7923 Mar 29 2019 network
-rw-r--r--. 1 root root 1160 Sep 19 21:52 README
-rwxr-xr-x. 1 root root 2437 Oct 19 2017 rhnsd
VS my ubuntu 19.04 laptop :
╭─x@meze ~
╰─➤ ls -al /etc/init.d/
total 244
drwxr-xr-x 2 root root 4096 Nov 17 13:17 .
drwxr-xr-x 147 root root 12288 Dec 17 06:49 …
-rwxr-xr-x 1 root root 2269 Mar 2 2019 acpid
-rwxr-xr-x 1 root root 5336 Feb 20 2019 alsa-utils
-rwxr-xr-x 1 root root 2055 Nov 29 2018 anacron
-rwxr-xr-x 1 root root 3740 Feb 25 2019 apparmor
-rwxr-xr-x 1 root root 2956 Mar 21 2019 apport
-rwxr-xr-x 1 root root 2401 Aug 21 2018 avahi-daemon
-rwxr-xr-x 1 root root 1175 Jan 25 2019 binfmt-support
-rwxr-xr-x 1 root root 2968 Jun 6 2018 bluetooth
-rwxr-xr-x 1 root root 1232 Apr 11 2019 console-setup.sh
-rwxr-xr-x 1 root root 3049 Nov 16 2017 cron
-rwxr-xr-x 1 root root 2804 Feb 16 2019 cups
-rwxr-xr-x 1 root root 1961 Apr 10 2019 cups-browsed
-rwxr-xr-x 1 root root 2813 Dec 5 2018 dbus
-rwxr-xr-x 1 root root 1172 Jun 6 2016 dns-clean
-rwxr-xr-x 1 root root 3033 Mar 16 2019 gdm3
-rwxr-xr-x 1 root root 985 Mar 12 2019 grub-common
-rwxr-xr-x 1 root root 3060 Jan 21 2018 hddtemp
-rwxr-xr-x 1 root root 3809 Jan 11 2019 hwclock.sh
-rwxr-xr-x 1 root root 2444 Feb 4 2019 irqbalance
-rwxr-xr-x 1 root root 3131 May 19 2017 kerneloops
-rwxr-xr-x 1 root root 1479 Feb 16 2018 keyboard-setup.sh
-rwxr-xr-x 1 root root 2044 Nov 13 2018 kmod
-rwxr-xr-x 1 root root 883 May 17 2016 lm-sensors
-rwxr-xr-x 1 root root 695 Dec 3 2017 lvm2
-rwxr-xr-x 1 root root 571 Dec 3 2017 lvm2-lvmetad
-rwxr-xr-x 1 root root 586 Dec 3 2017 lvm2-lvmpolld
-rwxr-xr-x 1 root root 4445 May 26 2018 networking
-rwxr-xr-x 1 root root 1942 Apr 2 2019 network-manager
-rwxr-xr-x 1 root root 5658 Mar 25 2019 nfs-common
-rwxr-xr-x 1 root root 9138 Jan 10 2019 openvpn
-rwxr-xr-x 1 root root 1366 Jan 25 2019 plymouth
-rwxr-xr-x 1 root root 752 Jan 25 2019 plymouth-log
-rwxr-xr-x 1 root root 612 Mar 15 2019 pppd-dns
-rwxr-xr-x 1 root root 924 Jun 6 2018 procps
-rwxr-xr-x 1 root root 1152 May 4 2019 resilio-sync
-rwxr-xr-x 1 root root 2480 Oct 14 2018 rpcbind
-rwxr-xr-x 1 root root 4417 Mar 15 2019 rsync
-rwxr-xr-x 1 root root 2864 Mar 7 2019 rsyslog
-rwxr-xr-x 1 root root 2224 Mar 24 2019 saned
-rwxr-xr-x 1 root root 1960 Jan 2 2019 speech-dispatcher
-rwxr-xr-x 1 root root 2484 Oct 3 2018 spice-vdagent
-rwxr-xr-x 1 root root 3939 Apr 8 2019 ssh
-rwxr-xr-x 1 root root 6822 Apr 11 2019 udev
-rwxr-xr-x 1 root root 2083 Aug 16 2017 ufw
-rwxr-xr-x 1 root root 1391 Apr 16 2019 unattended-upgrades
-rwxr-xr-x 1 root root 1306 Feb 23 2019 uuidd
-rwxr-xr-x 1 root root 6444 Jan 16 2019 virtualbox
-rwxr-xr-x 1 root root 485 Aug 11 2018 whoopsie
-rwxr-xr-x 1 root root 2757 Jan 20 2017 x11-common
So you’re probably outta luck with any version of Ubuntu… If you want a “cleaner” SystemD - maybe try a very recent release of CentOS or Fedora?
Well, Mr. Tripp, I appreciate your confirmation of the situation! Looks like I won’t worry about them any more…I’ll just watch, without touching. 
Would it be possible to delete these files without causing a system breakdown?
As long as you do a system backup first…As you are well aware, I am sure.
Here is the warning received with the above command line:
"WARNING: The following essential packages will be removed.
This should NOT be done unless you know exactly what you are doing!
e2fsprogs util-linux (due to e2fsprogs) init systemd-sysv (due to init)
sysvinit-utils (due to util-linux)
0 upgraded, 30 newly installed, 191 to remove and 0 not upgraded.
Need to get 1,962 kB of archives.
After this operation, 737 MB disk space will be freed.
You are about to do something potentially harmful.
To continue type in the phrase ‘Yes, do as I say!’ "