How can I enable UTF-8 support in the Linux console?

Check that you have the locales package installed

dpkg -l locales

If not, install it

apt-get install locales

As root, type

dpkg-reconfigure locales

you can navigate that list with the up/down arrow keys, for example choose en_US-UTF-8

edit your .bashrc by adding the following lines:

export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
export LANGUAGE=en_US.UTF-8

Run the localecommand ,the output should be similar to this::

LANG=en_US.UTF-8
LANGUAGE=en_US:en
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

Sure (it's limited on the number of glyphs, but it seems your locale is using UTF-8 encoding).

I use this for testing:

#!/bin/sh
# send character-string to enable UTF-8 mode
if test ".$1" = ".off" ; then
    printf '\033%%@'
else
    printf '\033%%G'
fi

and (calling it "utf8"), "utf8 on" turns the encoding on.

Using the example given with pstree, here is an example after running the script (before, the same sort of output as in the question):

As noted in a comment, there's a script unicode_start which does more, but all that is needed to address the question posed is the small script used as an example.

Addressing a different comment: At least on my system (and in the screenshot shown in the question), all of the characters used by pstree are supplied in the 512-glyph font used by default for Unicode support in the Linux console.

Further reading:

• console_codes - Linux console escape and control sequences
• Into the Mist: How Linux Console Fonts Work

Set CHARMAP="UTF-8" in /etc/default/console-setup.

Run systemctl daemon-reload && systemctl restart console-setup.service afterwards.