accented characters from the keyboard

[Séamas Ó Brógáin]

Just to expand slightly on what PleegWat and others wrote:

The method that Udvarias Ur mentioned does exist, but with some
conditions. There is a method of entering individual characters by
number that is supposed to be universal (it’s a formal international
standard), but it only partly works with Ubuntu (or I should say with
X11).

You hold down [control] and [shift] and then type [u]; you then type the
Unicode reference of the character––a four-figure hexadecimal number.
(The Unicode tables are freely downloadable from
www.unicode.org/charts.)

With X11, however, and therefore Ubuntu, you cannot have this function
as well as the [compose] key: you must choose one or the other.
(Strange, but true.)

In your /etc/environment file you must have a line like this:
        GTK_IM_MODULE=gtk-im-context-simple
or any other input method: ibus, scim, uim, etc.

For the [compose] key to work, on the other hand, you have to have
        GTK_IM_MODULE=xim
And you cannot have both.

To see which input method is active at the moment, in a terminal window
type
        echo $GTK_IM_MODULE

There is a roundabout method of having both functions. (1) Install the
extension “Compose Special Characters.” (2) Allocate a suitable function
key––say [F9]––to the “Unicode shortcut” in this extension. (3)
Customise your keyboard layout (as I explained in an earlier message and
can do again if anyone is interested) so as to allocate F9 to a suitable
key, say [AltGr]. Hey, presto! A “Unicode key.”

I should add that I am not an expert in these matters but discovered
these tricks through long and often fruitless searching. If anyone can
point out any errors, or add information, I would be very happy to hear
from them.