hello, how install Greek characters and how to switch Greek-English?

[vassi]

Keyboard layouts > press add
Don't go to "Limit language by selection"
Go to "layout" and select Greek
If not there you will have to install Greek language

sudo apt-mark hold linux-image-*     #Will stop you getting kernel updates
sudo apt update                               #Do not upgrade
sudo apt install ttf-ubuntu-font-family  # You might lose that install on the next bootup, so if you do, you will have to install the fonts whenever you need them.

Hello, it is all ok with Greek characters and  Greek language...


I have Maui install in persistent USB 16GB, what can i do for that(in Update):
Do you want to continue? [Y/n] Y 
Setting up grub-pc (2.02~beta2-36ubuntu3.6) ... 
/usr/sbin/grub-probe: error: failed to get canonical path of `/cow'. 
dpkg: error processing package grub-pc (--configure): 
subprocess installed post-installation script returned error exit status 1 
dpkg: dependency problems prevent configuration of grub2: 
grub2 depends on grub-pc (= 2.02~beta2-36ubuntu3.6); however: 
 Package grub-pc is not configured yet. 

dpkg: error processing package grub2 (--configure): 
dependency problems - leaving unconfigured 
Errors were encountered while processing: 
grub-pc 
grub2 
E: Sub-process /usr/bin/dpkg returned an error code (1) 
maui@maui:~$