I don't no much about Linux
I only try to open xorg-edit_07.08.11-0ubuntu1_amd64.deb.deb
but it seems I don't have gdebi ready.
then I downloaded http://packages.ubuntu.com/lucid/gdebi
and get the gdebi-0.6.0ubuuntu1 folder
but How should I install gdebi

best

Just...
connect to the Internet
open a Terminal
issue the command: sudo apt-get install gdebi

Job done.

but the terminal says sudo: apt-get: command not found
after I issue the command

If you're entering it exactly as you posted it there (with semi-colons), it's not going to work. It should be exactly this:

I entered sudo apt-get install gdebi, then terminal asks for password,
after entering password and press return, it says "sudo: apt-get: command not found".......

Wow, really? This may sound like a silly question, but what distro are you using? Ubuntu, for sure?

What's the output in the terminal of this:

This is a very good idea. Very good.

Would be nice if you would try it again and simply copy paste EVERYTHING that is on the terminal window.

Would also be good to try the command (copy/paste to terminal)
You should be asked for your password.

If you get an error message on that copy/paste everything on the terminal to here.

If you do not get an error copy/paste this to the terminal;
Don't add anything to that command.

su is the command used to get a root (#) prompt on Linux systems. Sudo is a shortcut and there could be a problem there.

One reason for determining your distro/version is to see what you are running. This should be in your signature along with some hardware info so people don't need to ask for it and you don't need to type it out in every thread.

If you are using Ubuntu, not one of the "family" members (Xubuntu, Kubuntu, Lubuntu, etc), then you are using a Gnome based OS. There has been some creeping instability in the Gnome terminal.

Another thing you could try is that last command I gave you (no sudo) at the root (#) prompt you get at the end of booting to recovery. If it doesn't work there you have a very interesting installation to say the least.

Tip: You do not need to type commands into the Terminal. Highlight the command written on the web page. Move your cursor anywhere in the Terminal and press your mouse wheel or mouse middle button. Automatic Copy and paste! No spelling mistakes! No Typos! No other errors!

today I downloaded "gdebi" and it does not work I did "apt-get install gdebi"
is it gives "E: impossible to find the package gdebi" how to help me please
I do not know if the "gdebi" works in 2018

You are replying to a post which has been inactive for 5 years. Best to start your own thread here

Did you prefix the command with sudo? It won't work otherwise. Which release of Ubuntu are you using. How did you download gdebi and from which location. You should be able to use the Software Manager also. THe commands below, run successively should work.

OK , lets do the easy way.

Open Menu - Administration - Synaptic Package Manager

Now Hit on Configuration - Repositories

Then Check button of your cdrom repository ( maybe you have 2 but check one of those) and apply the change.

Give "oK" to reload de repositories and close.

Then in packages list select "all" and make a search bY "gdebi" - select it and all the dependencies.

After installing, close Synaptic ( don t forget this) and go to the directory where are the package you want to install and right click over and choose "open with! ... Packages installer.

Et Voilá.

OK , lets do the easy way.

Open Menu - Administration - Synaptic Package Manager

Now Hit on Configuration - Repositories

Then Check button of your cdrom repository ( maybe you have 2 but check one of those) and apply the change.

Give "oK" to reload de repositories and close.

Then in packages list select "all" and make a search bY "gdebi" - select it and all the dependencies.

After installing, close Synaptic ( don t forget this) and go to the directory where are the package you want to install and right click over and choose "open with! ... Packages installer.

Et Voilá.