I am learning Linux, using Ubuntu. I wanted to remove network management from one of the run levels. I had done this correctly before, but now, no matter how hard I try, I can not remove a script from the desired run levels.
the rc3 folder is empty so how can I work on run level 3?!
Yes, with version 15.04 Ubuntu switched to systemd. The rcX.d folders are mostly obsolete.
You can use a configuration command like sudo systemctl disable network-manager.service to disable the network manager (which should leave the networking mostly unconfigured).
There are no runlevels in systemd, but an equivalent called "targets". tecmint lists the mapping like this:
- Run level 0 is matched by poweroff.target.
- Run level 1 is matched by rescue.target.
- Run level 3 is emulated by multi-user.target.
- Run level 5 is emulated by graphical.target.
- Run level 6 is emulated by reboot.target.
You can switch to a specific target via systemctl isolate multi-user.target. Symlinks usually exist, so you can also enter systemctl isolate runlevel3.target
In order to remove a unit from a particular target, you can modifiy the unit's WantedBy directive. Please be aware that targets can depend on each other, so removing a unit from a target will also remove it from the dependees.
