$ egrep -v '^$|^#' /etc/apt/sources.list
deb http://mirror.yandex.ru/debian/ buster main non-free contrib
deb-src http://mirror.yandex.ru/debian/ buster main non-free contrib
deb http://security.debian.org/debian-security buster/updates main contrib non-free
deb-src http://security.debian.org/debian-security buster/updates main contrib non-free
deb http://mirror.yandex.ru/debian/ buster-updates main contrib non-free
deb-src http://mirror.yandex.ru/debian/ buster-updates main contrib non-free
deb http://mirror.yandex.ru/debian/ buster-backports main contrib non-free
deb-src http://mirror.yandex.ru/debian/ buster-backports main contrib non-free
deb http://ftp.debian.org/debian/ buster-proposed-updates main contrib non-free
deb-src http://ftp.debian.org/debian/ buster-proposed-updates main contrib non-free
$ a="test";echo "$a";echo '$a'
test
$a
sudo cat /root/log
или из-под root
просто cat /root/log
#!/usr/bin/env ruby
# frozen_string_literal: true
require 'ruby2d'
set width: 300, height: 200
s = Square.new
s.color = 'red'
show