Linux - NewbieThis Linux forum is for members that are new to Linux.
Just starting out and have a question?
If it is not in the man pages or the how-to's this is the place!
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
You can't have this sort of information without knowing what kind of program you start I think. The latest link has an example of a program that's run via a terminal but dissociates itself from the controlling terminal. It's a normal practice for many daemons like smbd to drop its privileges to a special user
I wonder why you are even concerned about controlling terminals. Having one or not just affects the way you interact with a program, you are in charge over it anyways
Last edited by redfox2807; 12-12-2012 at 02:47 AM.
Could you be more specific? A program is always started by a user (i.e. with some user privileges) with the exception of init, that is triggered by Linux kernel directly. init defines and operates the whole user space. All the processes it triggers are run as root. Then in case of CLI login command is run. That's where a physical user comes into interaction with the system. As far as I can cogitate your intentions, your question goes to the area of user privileges, to define what a user is allowed to run and what's not. Maybe I'm just completely missing your point.
The concept of 'controlling terminal' is distinct from parental ancestry. All processes are children of some other process. The ps command shows the Parent Process ID (PPID). Is that the information you really want?
Any process can dissociate itself from a controlling terminal. Processes that do so are called daemons. Typically, these are launched as part of the system startup. Normally, a process is killed if it's controlling terminal closes (say, if the SSH connection is broken, or the modem hangs up, or an xterm gets closed). Daemon processes need to stay running perpetually, so cannot rely on a controlling terminal in order to stay alive.