configure gedit to always open in new window

I also need this. I suddenly find simpler solution:

sudo nautilus /usr/share/applications/

Point to gedit, hit Alt+Enter (Properties), and replace command to

gedit -s %U

Tested on Xubuntu 12.04.2 LTS. Hope it helps.

There is a gedit setting called notebook-show-tabs-mode, which is usually set by default to 'always', which means every new document opened will open in a tab. However, if you set it to 'auto' by entering the command below in the terminal, gedit will not open in a tab unless another document is currently open.

gsettings set org.gnome.gedit.preferences.ui notebook-show-tabs-mode 'auto'

However, if you want to make sure that no tabs are ever opened, choose the 'never' setting, so that is probably what you want. You may then need to use the File menu within gedit to switch between documents, although gedit will still warn you when you try to close it if there are still unsaved documents. This is the command you want in this case:

gsettings set org.gnome.gedit.preferences.ui notebook-show-tabs-mode 'never'

To return to the default settings, use 'always' in the command above instead. You can also find the whole list of hidden settings for gedit by entering

gsettings list-recursively | grep -i gedit

but I think the notebook-show-tabs-mode setting is maybe the one you want.

However, after considering your comment, I think you could also use the standalone (-s) gedit option, as that will open each new document in a new window. Create a .desktop file like this and make it executable and put in ~/.local/share/applications:

[Desktop Entry]
Type=Application
Name=gedit_alternative
Comment=gedit standalone
Exec=/usr/bin/gedit -s %U
Terminal=false
GenericName=

Then simply associate it with text files by editing ~/.local/share/applications/mimeapps.list and add the following to these sections of the file (backing it up first):

[Default Applications]
text/x-log=geditspecial.desktop
text/plain=geditspecial.desktop

and

[Added Associations]
text/x-log=geditspecial.desktop;
text/plain=geditspecial.desktop;

Replace geditspecial with the name of your own .desktop launcher. Now when you click text files they will all open in separate instances.

For Nautilus and other GUI instances

Edit your /usr/share/applications/gedit.desktop file add the argument --new-window to the Exec= entry:

Change from:

[Desktop Entry]
Name=gedit
GenericName=Text Editor
Comment=Edit text files
Exec=gedit %U
Terminal=false

Change to:

[Desktop Entry]
Name=gedit
GenericName=Text Editor
Comment=Edit text files
Exec=gedit --new-window %U
Terminal=false

For the commandline

That takes care of the nautilus and other gui instances. For the commandline use the alias in ~/.bashrc as mentioned by Leocadio González Casado above. Append this to your ~/.bashrc file.

alias gedit="gedit --new-window"

Note:
This works with all Ubuntu versions.