UNIX for Dummies Questions & Answers

Hi,

I was not sure about the terminology of the thing that I am about to explain, so it was very difficult to find relevant search results.

I want to use my computer using the ctrl+alt+f1 CLI without using a graphical system. However, at the same time, I would also like to do basic tasks like reading a PDF or open a browser. Switching back to a GUI for these tasks are quite distracting. Is there a way that I can launch windows under the CLI interface and somehow overlay them over the CLI?

Any pointers would be much appreciated.

Hi jamie_123...

Do you mean with a transparent background on any window/screen overlaying each other?

I have no idea what you are trying to do but with Linux you can have multiple _desktops_ with apps running inside each _desktop_.

Each _desktop_ sits on the _taskbar_ and just one click on each will put you onto each one.

How about multiple monitor outputs?

Hi wisecracker,

My question was more to do with only CLI and launching graphical applications from the CLI. For example from a tty shell like thishttps://www.google.se/search?q=ctrl%...aIxRj_X3NyM%3A

It is much easier than you are thinking: a UNIX system (your Linux, as i can tell you use, is no exception) has a (theoretically) unlimited amount of possible terminals attached via "serial lines" (see "RS232" about what a serial line is). This is the basic way you connect to a UNIX system.

Your Linux has a graphically-enabled terminal, which you use to connect with locally and which runs an X-Window-system: a so-called "X-Server" (picture it as a driver for your graphic card plus a library with some function calls programs can use, providing graphic primitives like "draw line", "draw rectangle" and so on), a Window Manager on top of it and on top of this are some programs running (like Firefox, Open Office, etc.) which use the services these underlying programs provide. This is what you perceive as "your desktp".

At the same time you can connect to your system also at a more basic level, via classical serial terminals. Your system initially creates 7 of these (virtual) terrminals, between which you can switch with CTRL-ALT-F1 through CTRL-ALT-F7. In the seventh one (reachable by CRTL-ALT-F7) your graphical environment runs.

But terminals can be created on the fly and there are programs running under the X-Window-System (just like our Firefox) which provide such terminals. These programs are called "terminal emulators" (because they emulate a piece of hardware which is out of use today for most people, but still sets the standard of how things work). The most common one is called "XTerm" and they all operate more or less the same way: they create a window, start a shell inside it and when you leave the shell the window closes. You can run several instances of these emulators side by side and this way have several windows with open shells at the same time.

I hope this helps and you got some general knowledge and terminology out of it too. If you still have questions just feel free to ask.

bakunin

Hello bakunin,

Thank you for the detailed answer. I can try to reformulate my question based on your response.
So I am running a linux box using the classical terminal (CTRL+ALT+F1-F6), the machine has an x-window system installed as well, which I do not want to use to launch programs. The scenario that I was thinking of was to launch a graphical program from one of these classical terminals. I was wondering, since I have x-window installed, it must be possible to create a window on top of the classical terminal somehow. I hope my question makes more sense now?

Thanks.

Nope, unless you write your own X or Wayland, that will but itself ontop of the VT (as in VT1-VT6).
To start applications from the cli, you must either be in a terminal window so you can start GUI applications, or if you're on a VT, the application must be a CLI tool.

There are several applications that work on the CLI, from email via IRC to torrent clients and much more (alsamixer for example).

These kind of applications (binary) are usualy written using ncruses.
If you like to have an interface like feeling on the console using scripts, TUI could be of help.

hth

hmm - didn't you want to have several CLIs at once? Now i am confused about what you in fact want.

The question makes sense, but it isn't possible to do so. Graphical programs are graphical, because they use certain (graphical) functions: on a terminal to display character "a" you simply send an "a". On a graphical application, to display an "a" you need to decide in which font you want it displayed, get the (graphical) definition of the character "a" in the font and the respective size, finally use some graphics routines ("draw line", "draw curve", "fill area", etc.) to finally display a picture resembling an "a". All these functions are carried out (via several layers of software) by the underlying libraries (the X-Server and the Window-Manager) so that for the application itself it boils down to simply order "display an 'a'" again. But without these layers of software underneath the order would not make sense.

If your goal is to start a graphical application using a X-Server running somewhere else (on local hardware or some remote system on the network): this is possible, in fact it is the normal use one makes from graphical environments.

When you start a program (an "X-Client", because it uses services) it needs to be told which X-Server (a program which provides these services) to use. This is is done via an environment variable called "DISPLAY". For instance:

Code:

# export DISPLAY=myrunningxserver.network.org:0.0
# /usr/bin/firefox &

This will (if everything is configured correctly) make firefox run on the system you issued the command but display its window at the system "myrunningxserver.network.org" at display 0 (there could be several displays), screen 0 (every display could consist of several screens).

If you want to know more about how X-Windows works i suggest to read this thread

I hope this helps.

bakunin