[SOLVED] Launch systemd service before login prompt

JuventusFC · 08-25-2021, 07:31 AM

After being able to change the hostname on the fly, I am trying to run a systemd service before the login prompt, as the first time It asks for login credentials, the value printed on the screen refers to the previous content (previous startup) of /etc/hostname.

I already tried what is suggested here, but It didn't work for me

EDIT: It has some dependencies with other services as well, so launching the hostname-changing service as one of the first ones (i.e. DefaultDependencies=false) is not an option

michaelk · 08-25-2021, 07:58 AM

Quote:

as the first time It asks for login credentials, the value printed on the screen refers to the previous content (previous startup) of /etc/hostname.

Not exactly sure what you are trying to accomplish. Without seeing your script anything you try to print or echo will not be displayed since the running script is not associated with the desktop or login manager.
However Depending on what desktop/login manager you are running it is possible to add a banner to the login screen.

JuventusFC · 08-25-2021, 08:31 AM

Quote:

Originally Posted by michaelk

Not exactly sure what you are trying to accomplish. Without seeing your script anything you try to print or echo will not be displayed since the running script is not associated with the desktop or login manager.
However Depending on what desktop/login manager you are running it is possible to add a banner to the login screen.

The message would have to be shown on a CLI-only interface so It will be actually shown

michaelk · 08-25-2021, 08:59 AM

However, service start up messages are displayed but are cleared before the login prompt.

One way would be to have your script modify the contents of the /etc/issue file. /etc/issue is banner that is displayed before a user logins.

In the old days before systemd rc-local was a script that could run as the last step before login. Now you can create a similar feature using a service.
https://www.cyberciti.biz/faq/how-to...-linux-system/